Outlook 2010 Sync Issues Folder is full of sync logs (“Synchronization Log:” and “Modification Resolution”) with Exchange 2010 Mailbox

After I moved my mailbox to Exchange 2010, I started seeing two kinds of Sync logs in “Sync Issues” folder: “Synchronization Log:”  and “Modification Resolution”.

Whenever I delete something and empty my “Deleted Items” folder, I see a sync log in a minute. It says,

22:45:33 Uploading to server ‘CAS1.company.com’
22:45:33 Synchronization of some deletions failed.
22:45:33          [0-130]

22:45:34        1 view(s)/form(s) updated in online folder
22:45:34        4 view(s)/form(s) deleted in online folder

For the record, it doesn’t happen if my Outlook is on ONLINE mode. It only happens in Outlook Cached Mode.

It drove my users crazy. It seems it drives lots of people crazy as I read in technet forums. So far no one finds solution for this. There are many explanations why it happens, but no solution. Exchange 2010 SP1 doesn’t fix this issue either. Well, I have been told it’s Outlook 2010 related issue, not an server problem.

I called Microsoft support and they confirmed they themselves are getting this logs. Sad smile If you find an solution, please reply to this blog. Or hopefully next Office 2010 service pack fix this one.


Whenever I did something with Calendar items (deletion or modification), I see “Modification Resolution” log in Sync Issues folder.

14:30:00 Message class: {SU:IPM.Appointment}
14:30:00 Appointment Conflict Resolution
14:30:00 Local subject: {SU:Team Lunch – Placeholder}
14:30:00 Remote subject: {SU:Team Lunch – Placeholder}
14:30:00 Local Message Entry ID: {CB:70, LPB:0x00000000D7754433D4F990489C0A23AA08ED28C307005EF0C574BA12B14F805532F0BB58596200000A794FE70000FE23979F836CCA43B84FC495B894A5110000003B56A30000

14:30:00 Not equal (conflict) named property: 0x00150003
14:30:00 Conflict Merge named property: 0x00150003
14:30:00 Critical properties merged into remote item.
14:30:00 Successfully auto-resolved

I heard BES server also generates these logs consistently.  I came to know how to stop “Modification Resolution” logs. Modification Resolution log explains what Outlook did on a conflict on items. To stop generating this log, create a registry entry as below with option 0.

Key: HKEY_CURRENT_USER\ Software\Microsoft\Office\14.0\Outlook\Options
DWORD: EnableConflictLogging

0 = Never save Modification Resolution logs
1 = Always save Modification Resolution logs
2 = Save Modification Resolution logs when a "critical conflict" occurs
<This is the new Default behavior when the EnableConflictLogging dword does not exist.>

150 thoughts on “Outlook 2010 Sync Issues Folder is full of sync logs (“Synchronization Log:” and “Modification Resolution”) with Exchange 2010 Mailbox

  1. Many users are getting this sync logs everytime they send mail. Its accualy driving everyone crazy. Any solution to this?


    1. Kuda,
      So far no solution from Microsoft. I am waiting for Office 2010 service pack. Since Microsoft knows this issue (they themselves suffer from it), I am hoping they will fix it on next service pack.

      Other way is to write a VBA script to clear the SyncFolder contents and distribute it via GPO. I don’t have time to spend to try out solutions.

      Good Luck.


      1. i found that blowing away my local OST file and letting Outlook rebuild it from our Exchange server this problem for me.

    2. Hi, Try new with latest features eSoftTools OST to PST converter software that is capable to convert all OST data into PST,EM,EMLX,HTML and so many other formats. you can try it’s trial version also that is capable to convert 25 mails into PST format ans trial version is free of cost.

      Download now:http://www.esofttools.com/ost/

  2. Similar situation here too. Odd thing though is that the Windows 7 laptops running with cached mode don’t seem to be experiencing this issue at all, but all the XP SP3 laptops are. Anyone else want to comment on what OS they are (or aren’t) seeing this issue with? Laptops with the problem are also showing Event ID 9646 on the Exchange 2010 server as well.

  3. Thanks for the blog. You saved me from hours of wasted troubleshooting. Wish I’d have known the same thing about searching our network drives with Win 7/Server 2008 R2 “search” LOL

  4. Getting the same thing here when deleting email/contacts/calendar items. Also I noticed that I cannot download the Offline Address Book during a send/receive.

  5. Outlook 2007/2010 Sync Issues with Exchange 2007/2010.

    Sync Issues:
    Synchronization of some deletions failed.
    Also, Offline Address Book.

    I migrated our Exchange server from 2007 to 2010 SP1 on a new domain and am running both Outlook 2007 and 2010 on the desktop. When I looked at our sync issues I found that while I had a UCC (multi- SAN certificate) on the mail server with internal and external names, I forgot to setup both A and SRV records for AUTODISCOVER in both the internal and external domains. (Firewall has loopback, so I keep external domain names at the registrar only and don’t duplicate them on internal DNS. Resolves VPN / OWA issues.)
    Once I created both the A and SRV records in both internal and external domains, flushed server cache and ran ‘ipconfig /flushdns’ on the workstation… the Sync Issues automatically cleared themselves up. Verified this on another workstation. I’m letting the TTL expire on the 60 odd workstations to clear up their errors… keeping my fingers crossed!

    Forward Lookup Zone | Other new Records | SRV
    Service: _autodiscover
    Protocol: _tcp
    Priority: 0
    Weight: 0
    Port Number: 443
    Host: servername.intdomain.local

    AUTODISCOVER (SRV) in GoDaddy:
    Add and SRV record.
    Service: _autodiscover
    Protocol: _tcp
    Name: extdomain.com
    Priority: 0
    Weight: 0
    Port: 443
    Target: servername.extdomain.com
    TTL: 1 hr

    Your mileage may vary. Enjoy!

  6. Yes, I do have correct autodiscover SRV records. It is the client issue and not at all server side problem. Since this doesn’t happen on Outlook 2003 and Outlook 2007/2010 online modes, something wrong in Outlook 2007/2010 offline mode access algoritm or bug.

  7. I have this problem and it is killing me. The biggest problem it causes is that some folders are not synchronized and therefore the server has for example 60 messages in folder “XYZ” but on my laptop it only has 58 messages. This is really difficult situation and I need solution fast. I can’t possibly work with ONLINE mode instead of cache mode because it takes forever to load bigger folders. MICROSOFT PLEASE HELP!

  8. I have applied Office 2010 SP1 in my Exchange 2010 SP1 RU4 environment, and it has not stopped these rogue Synchronization Log entries.

  9. i was able to resolve this by adding both of my mail servers to DNS forward lookup zones (internal dns only) as MX records. Then deleted my outlook profile completely and recreated it. no more sync issues, at least not yet. Exchange 2010 ver 14.1 build 218.15, outlook 2010 ver 14.0.4760.1000 32bit on Win7 32bit.

  10. I had found this registry solution a while ago on another site. I created the registry key and the problem stop for a month or so. Now, I’m getting the Modification Resolution logs again even if the key EnableConflictLogging is set to 0. Reading this comments I see that I’m not the only one. 😦

  11. Out of an office of 20 I’m only experiencing this issue with one computer. I’ll try the DNS suggestion above, other than that has anyone else found a good fix.

  12. I just installed office Pro plus 32 on my Windows 7x 64 OS Home PC. Having same Sync Issues. Need Help!! Spent $1,200.00 to upgrade hardware. This sucks at best

  13. I had this error occurring for a user who disabled the “Save copies of messages in the Sent Items folder” setting in file > options > Mail > Save messages. Once I enabled the setting the sync errors were no longer an issue.

    Server: Exchange 2010
    Workstation: Outlook 2010

      1. Take a look at any rules setup on the outlook client. I would try disabling all rules and see if the sync errors continue. I found that disabling “Cached Exchange Mode” stopped the sync errors which allowed me to focus on the client and not the server for a resolution to my issue.

  14. Guys, looks like I solved it!!! 🙂

    In my case, I had a second account opened in my Outlook 2010 which I wasn’t able to synchronize at all using Cached Exchange Mode. It worked ok in full “online mode”, but no way to let it sync using Cached Mode.

    Today I discovered an (sort of) hidden option inside the “Send/Receive” ribbon, under “Send/Receive Groups” –> “Define Send/Receive Groups”. A popup window will open, where you’ll have an “All Accounts” Group: select it and click on the “Edit…” button on the right side. This will open a further popup: here you’ll want to be sure that for each and every account, you have selected (ticked) the option “Include the selected account in this group”, which is on top of the window, and select also “Send mail items” and “Receive mail items”, slightly below.

    As far as I can see, now my mailbox is synchronizing again like charm!

    Hopefully this will help anybody who already tried to rebuild the “ost” file like I did several times, without solving the issue.

      1. same here. I tried 450 sync log [0-130] issues since Friday 1/13.

        We have Exch. 2010 in a VM and OL 2010 32bit on Win7 Ent. 32bit. Company wide issue.

  15. Christiano – Since you just tried you solution, can you please let us know in a week if it is still working?

    I have a few users who this is driving kinda batty …

  16. Hi

    I am also getting sync errors on Outlook 2010 and Exchange 2010 but only for users in one site. Below please find part of sync log

    15:26:47 Downloading from server ‘XX123.xx.xxx.com’
    15:26:48 Synchronizing Forms
    15:26:48 Downloading from server ‘XX123.xx.xxx.com’
    15:26:48 Error synchronizing folder
    15:26:48 [80004005-501-4B9-560]
    15:26:48 The client operation failed.
    15:26:48 Microsoft Exchange Information Store
    15:26:48 For more information on this failure, click the URL below:
    15:26:48 http://www.microsoft.com/support/prodredirect/outlook2000_us.asp?err=80004005-501-4b9-560
    15:26:48 Done
    15:26:53 Microsoft Exchange offline address book
    15:26:53 0X80190197

    15:09:10 Synchronizer Version 14.0.4760
    15:09:10 Synchronizing Mailbox ‘Smith, John (XX – New York)’
    15:09:10 Synchronizing Hierarchy
    15:09:36 Error Synchronizing Hierarchy for Mailbox ‘Helpdesk New York, (XX – New York)’
    15:09:36 [80004005-501-4B9-1900]
    15:09:36 The client operation failed.
    15:09:36 Microsoft Exchange Information Store
    15:09:36 For more information on this failure, click the URL below:
    15:09:36 http://www.microsoft.com/support/prodredirect/outlook2000_us.asp?err=80004005-501-4b9-1900

    Any ideas?

    Thanks in advance

    1. Yep, I can confirm that the process I described in my post was successfull in my case. But I can understand that most of you are maybe in a different situation than I originally was.

  17. We’re getting this problem too…. MICROSOFT, fix your stuff! Anyone have any other ideas on this? Doesn’t seem to be any real solution other than disabling cache mode..and for our users at remote sites, this is not really an option. help?

      1. This is the first time I am hearing Outlook Online mode is not resolving the issue. Sync error happens because it compares and update the changes to the Outlook cache. Outlook online mode is what you looking at the changes in real time, thus no possibility of this error. Can you double check your settings?

  18. You are right – when I went back and checked my settings the cache mode was enabled. I have disabled it and will let you know results.


  19. for my clients who have this problem, every time there is in the loop, using a mobile as blackberry, ipad, ect ..

    You too?

    1. I don’t use it on mobile devices very often. Only when I’m traveling and don’t have access to a computer (which is rarely). I have not noticed that though the few times I have access my mail through my phone.

      By the way, so far so good no error messages since I disabled the cache mode.


  20. This resolved my sync issues. Log out of Outlook. Rename your offline data file from outlook.ost to outlook.ost.old found here C:\documents and settings\LoginID\Application Data\Microsoft\Outlook. When you log back onto Outlook, it will recreate this file.

    1. Nope, that will not resolve the issue. Wait for sometime, those SyncIssues posts will show up soon. Try accessing emails on your phone (delete an email if you can), Outlook will log SyncIssues post right away.

    1. Yes, that KB article says,
      “Microsoft is researching this problem and will post more information in this article when the information becomes available”.

      Hopefully they update the same KB article when they resolve it.

  21. This problem is driving our whole office crazy. Anyone have a real solution to make the offline folders match up to the server?

  22. Having this with a user’s mailbox, large mailbox and has a secondary added through Advanced Settings, another that shows up on it’s own after giving him full rights for this third mailbox. He moves messages back and forth. I have removed Download Shared folders, but left it on Cached. Once you take it off, it seems to take it off for his main mailbox. I’ve archived much of the mail in both. Changed and recreated OST files as well. Lots of sync issues, and only when in cached mode. Windows 7, Exchange 2010 SP1, Outlook 2010.

  23. what kind of A/V software are you all running?
    Is it scanning the OST file for changes? Or email traffic (inbound/outbound)

    Disable it and see if you still have issues.

    1. True, but it happens to who don’t have BES server in the enterprise. So you may resolve the duplicate sync errors, but you will receive sync errors just for the account of Exchange bug.

  24. Hi all

    I’m having similar issues. I’m an external remote consultant for a company who is running Office 365. I have WinXP latest SP, plus Outlook 2010 on a desktop. I have nearly 6,000 sync error messages in that folder, along with one item in the Conflicts folder. But, that item just got added on Mar6, and my sync errors go back to Jan3, the date I started my consultation.

    I already had enabled the “Save copies of messages in the Sent Items folder” setting, so that didn’t fix it.

    I can’t find where to select Online vs Online Cached Mode on the client side. Where do I do that?

    Here’s a calendar problem I think is directly related. Monday (Apr2) my entire Outlook calendar (the one under the consulting account) went 100% blank. Not only that, but a 2nd calendar (again specifically for the consulting account) appeared – also 100% blank. These are both in addition to the Local Calendar I have. I use many IMAP accounts in Outlook. First I saw of this problem was Sunday night, perhaps early AM Monday morning, when I checked what my calendar looked like for Monday. It was literally *blank* which never happens.

    I think the massive number of syncs (and whatever is causing those log entries to appear) has now borked my calendar, too.

    Couple more details that might be pertinent…
    I use my iPhone attached to the Exchange account (consulting one)
    I use SalesForce for Outlook, which also sync’s to the same account. SF only sync’s emails – I disabled tasks and events (calendar stuff) a while back.

    Any help would be appreciated!


  25. One other thing. I can confirm for my situation, disabling all local client Rules did nothing. I disabled those at 2:30pm today, and had a sync error appear at 3:46pm. I will keep an eye on it, but I don’t think that changed anything.

  26. I had a lots of sync errors in outlook 2010 with office 365 and shared calendars. I fixed th problem by doing following:
    1. uncheck the outlook “Cached Exchange Mode” from email account settings
    2. delete all shared calendars
    3. restart outlook
    4. go to account settings and check the option “Cached Exchange Mode” again (also check the option “download shared folders”
    5. restart outlook
    6. go to calendars and open shared calendars again

    I don’t know if those restarts are needed, but this got it working at least for me. Now I’m going to test this with another computers and office 365 accounts. Hope this will fix the problem 🙂

  27. Hey Guys

    Any luck with this? what is the outcome. This is driving me crazy. Appreciate any help on this

  28. I have reproduced the issue: Turn cache mode on. Send an email and then drag that email out of the sent items folder into a PST file before sync’ing the sent items folder in the mailbox. Sync the sent items folder in the mailbox and the sync issue occurs. Conclusion: Sync issues occur when cached mode is turned on and an email is moved out of the mailbox before the mailbox is sync’d with the server.

  29. Howdy I am so delighted I found your blog page, I really found you by accident,
    while I was browsing on Yahoo for something else, Anyhow I am here now
    and would just like to say thanks for a fantastic post and a all round exciting blog (I also love the theme/design), I
    don’t have time to look over it all at the moment but I have book-marked it and also included your RSS feeds, so when I have time I will be back to read more, Please do keep up the superb work.

  30. Hi

    After ripping my hair for months Sync Logs kept coming no matter what. Doing everything and else listed all around the web and here . I finally concluded that this problem is not related to the client and/or outlook but the Exchange DB somehow.

    Switched to online mode, closed outlook, deleted OST.

    RDPed to the server, moved the mail box to another mailboxdatabase with 50 corrupt item skips.
    Moved it back again.

    Launched outlook, switched to cached mode again.

    11 th day with no issues…

    Ps: iPhone with push is enabled on the mailbox.

    1. Found this link.


      You can work around this issue by stopping the Modification Resolution logs, which provide a description of the actions that Outlook took during a conflict situation. To stop the Modification Resolution logs, configure a registry key as described in the following table, and set the value to 0:

      HKEY_CURRENT_USER\ Software\Microsoft\Office\14.0\Outlook\Options
      0 = Never save Modification Resolution logs
      1 = Always save Modification Resolution logs
      2 = Save Modification Resolution logs when a “critical conflict” occurs
      Items appear to be expired in Outlook but are not removed by Exchange Server

      1. Verified on Outlook 2013 (15.0) with Exchange in the cloud.
        Thank you, thank you, thank you!

  31. There is also a group policy setting that achieves the same thing:

    User Config/Policies/Administrative Templates/Microsoft Outlook 2010/Outlook Options/Other/Advanced

    Prevent saving sync conflicts – [Enabled]

  32. I have a work around.
    uncheck empty deleted items folder when exiting outlook (options,advanced
    setup autoarchive on the deleted items folder to permenantly delete contents every day or one a week .

    the sync issue seems to happen because outlook goes offline before emptying the deleted items folder

    1. Thank you Ivan!! I have been searching for this everywhere!

      1.Click Start, click Run, type regedit, and then click OK.
      2.Locate and then click the following subkey in the registry(Or CREATE Key “Cached Mode”):
      HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Cached Mode

      3.On the Edit menu, point to New, and then click DWORD Value.
      4.Type “ANR Include Online GAL”, and then press ENTER.
      5.On the Edit menu, click Modify.
      6.Type 1, and then click OK.

      (Modified a bit from site Ivan Suggested: http://support.microsoft.com/kb/831124)
      Good luck all!

      1. Jesse – Sorry this is late, I didn’t get an email until today that there were new posts. Sadly no, I still have the issue with all of my users. Still looking for the answer to my problem. 😦


  33. We have several clients at one company having the same issue, the work around is a follows:
    Set outlook to online mode, perform archive of the mailbox to reduce the size and number of emails. Delete the current OST file, then set cache mode back on and the sync issues should be resolved, if it does not archive more.

  34. I’ve read through each and every posts on this page and have tried out the work-around solutions, but still no luck. Has anyone found the solution yet? Thanks!

    1. After chasing my tail for weeks, I deleted the mailbox waited for a few days then recreated. Never had the problem again… Its months now.

      1. To delete all the mailboxes and then recreate them. Wow if we only had a few mail clients that would be ok but that is a pile of work for a little problem. I am going to make a rule to just delete those emails when they come in.

    2. I combined few works around from various site (including the ones from this site) and it works well for me. So, i would like to share it with everyone. Hopefully it will resolve your annoying issue with the “Synchronization Log:” email.

      Here are the instructions to turn it off:

      1. Click on File -> Options
      2. On the pop-up window, select Advanced on the left panel
      3. On the right panel, scroll down, and click on the Send/Receive button
      4. On the pop-up window, click on the Edit… button, which will open up another pop-up window
      5. Check Include the selected account in this group checkbox and then check the Send and Receive items checkboxes
      6. Click on the OK button to save and close out all other pop-up windows.

      Steps 1-6 above would solve this issue for most people. If you still getting the “Synchronization Log” email after completing those steps, please continue with the steps below:

      7. Click on “Unread Mail” folder on the left column of your Outlook
      8. Click on the “View” tab on top of the screen
      9. Click on “View Settings” button
      10. Click on “Filter…” button
      11. On the pop-up window, click on the “Advanced” tab
      12. For the “Field” dropdown, select “Frequently-used fields” and then select “Subject”
      13. For the “Condition” dropdown, select “doesn’t contain”
      14. Enter “Synchronization Log:” in the “Value” field and click “Add to List” button
      15. Click “OK” button few times to close it out

      Completing steps #7 to #15 above will customize the view for the “Unread Mail” folder not to show the “Synchronization Log:” emails.

      ….and if that still did not solve your issue, here are the last trick:

      16. Hold down the “Windows” key on your key board and press “r” to invoke the “Run” program
      17. Type in regedit and click on the “OK” button to open up the “Registry Editor” window (Windows will ask for your permission, just click on “Yes”)
      18. Expand the following keys:
      HKEY_CURRENT_USER > Software > Microsoft > Office > 14.0 > Outlook

      19. Select the “Options” folder on the left
      20. On the right panel, double click on the “Default” and enter 0 and save
      21. Close out “Registry Editor”

      The steps above will tell Outlook not to bother reporting the “Synchronization Log:” email because you won’t care about it.

      It has been few days now and I haven’t received any “Synchronization Log:” emails.

      1. I had to do all 21 steps but so far this solution is working for me. I am using Outlook 2013 but I had the problem all through Outlook 2010 with Exchange 2010. Nice to maybe finally close this one for me. (Knock on Wood).

  35. we are having the same issue but not on exchange 2003, our users are running either outlook 2010 and 2007, the server data size shows a lot of sync failures and conflicts which is filling up their mailboxes. any help will be appreciated.

  36. I found a weird work around. This has been driving me crazy for a while.
    -On the “Unread Mail” folder right click.
    – Select “Customize This Search Folder”
    -Click Browse.
    -De-select “Search Sub folders”.

    This solved the problem for me so far…of course the stuff that is unread is not showing up in the “Unread Mail” folder anymore either…but if you do have unread items you will see them show up next to the folder they are in. EX. if you have an unread email in your Inbox if you look at your Inbox folder it will show: Inbox [1] for when you have an unread item in it.

  37. I have a single computer at a client having the same issue. Exchange Server 2010 (14.02.0328.009) running on Server 2008 R2. The client is running Windows XP SP3, Outlook 2010 SP1. Waiting for a fix from Microsoft…..

  38. After checking out what “czgurl” suggested I played around with those options, and came up with these settings inorder to get all your unread messages in the Unread Mail folder:
    -On the “Unread Mail” folder right click.
    – Select “Customize This Search Folder”
    -Click Browse.
    -If necessary, click the arrow next to the email account to get all the subfolders under it
    -De-select the email account
    -Select all the other options that you want
    -OK your way out

    Some of my users have around 100 subfolders, so being able to use the Unread Mail folder is a must. I haven’t tested it for long, but if you are going to try CZGURL’s suggestion then I suggest you use this in case any of your users are like mine.

    1. Hi

      Amazing that this thread has been going since 2010, did the exchange service packs and updates never solve the issue of Sync folders filing up?

      1. Nope…..im still having the same problem!

        Also noted that their appears to be a sync issue with “Views” as well

    2. I turned off Office 2010 Upload Center Sync and none of my users are getting sync errors or logs anymore.

      1. Hey Felicia,
        Can you tell me exactly how you turned it “off”? I went into Settings and unchecked all the check marks, deleted my cached files, and still get the errors in my Outlook. Did you do it in the server? If so where did you go to do it at? Thanks!!

      2. Like Tina… Would you mind sharing exactly how you disabled these messages? We’re using offie365 and have the same error logs

  39. Following Tuan’s advice from January 24th above, I applied those steps to a client with this issue (Outlook 2010 and Exch2010) on a peer-peer network. One of the steps included hiding items from view based on the subject line. It appears that using the “Advanced” tab functionality will not allow an “OR” situation (we need to hide subjects with “Synchronization Log” and those with “Modification Resolution”). I used the SQL tab instead, but guessed at the syntax as I found no concise, exact reference for it.

    Here’s the syntax to add to the SQL tab to get those two email subjects hidden from view:

    NOT (“urn:schemas:httpmail:subject” LIKE ‘%Synchronization Log:%’) AND NOT (“urn:schemas:httpmail:subject” LIKE ‘%Modification Resolution%’)

    Note that it did NOT prevent the counting of unread items in the folder as indicated by the integer in parentheses to the right of the folder name.

    The immediate effect of the remainder of Tuan’s advice seems to have worked so far, but I just applied it (and hadn’t restarted the pc yet). Test emalis sent immediately after applying all of Tuan’s steps did not result in the typical Sync Log issue.

  40. Go into your account settings and turn off Caching. Restart outlook and it will be better. If outlook is too slow for you after that just turn it back on, restart Outlook and hope that you don’t get the same errors.

  41. I found this information for opening the Sync Center. I’m not a tech so I don’t know how much it will help.

    Open Sync Center

    Sync Center displays your sync results if you’ve set up your computer to sync files with a network server. This allows you to access files stored in a network folder, even when that folder is unavailable by making it available offline.

    Click to open Sync Center.

    Sync Center can’t be used to sync devices with your computer. For information about that, see Sync music, pictures, contacts, and calendars with a mobile device.

    Here’s another way to open Sync Center: Click the Start button . In the search box, type Sync Center, and then, in the list of results, click Sync Center.

  42. Hit here, we tried the reg-key solution to suppres the modification resolution mails, and it worked..
    For about 6 months, and since 2 day’s the mails are coming back again, I checked the registry, the key is still there and set to ‘0’. Anyone an idea?

  43. I think it is outrageous that this trhead is still active after all these years…We have different customers in on-line and on-premis environments all suffering the same problems. end-users are afraid they are missing out on messages, and will sooner or later all call for support. Where can I send the bill?

  44. We are having the same problem, but not with all users. I get one sync log a day, when I log in in the morning. Another user is having two or more a minute show up. I renamed her ost file last week and let Outlook build her another one. I think a couple of other people in the office are having the same problem. If it was an Exchange problem, I feel like it would happen to all of us. Does no one know YET what causes this, and what fixes it?

  45. Check add ins. In my case as soon as I turned off Business Contact Manager (which the user wasn’t using), the sync folder cleared all of the sync issues and I haven’t seen them again.

  46. In our situation, I’ve tried many of the suggestions above (and numerous ideas from other forums), but it appears the problem is related to Outlook Add-Ins for us. I disabled several Add-In and I suspect the Kaspersky AV and AS plug-ins are to blame. Still testing this theory, but so far so good.

  47. I am having similar problems but not identical. My Outlook 2013 is constantly syncing my junk mail folder. So I am getting thousands of sync issues in my sync issues folder. Don’t know what to do.

  48. I have a client running Outlook 2013 on Win7 Pro 64bit with the same issue. I unchecked to “Use Cached Exchange Mode”, restarted Outlook and it the errors when away. Hopefully they STAY AWAY 🙂

  49. Had the same Issue as all above. Don’t delete anything, it seems to be a simple fix that requires you to read the sync log error. That is look at message and the folder that is providing you with the sync fault. Go to that folder and right click on it, go to properties, then go to permissions, once there add the users name. This solutions works, but can be a bit of an administrative task if you have a number of users. Good luck, let me know if this solution helps.

  50. Easy sollution to at least hide the problem: Right click the mail and choose “Block this sender”. Works for me so far.

  51. i configure my gmail in outlook 2010…i get problem to sync my sub- folder which i create in Inbox (my b i have more then 90 folder)..

    Every time i sync…Each and Every Folder …it will take more then 3 hours…please i need solution for this …


    Abdul lateef

  52. As a side note, don’t forget to install Office 2010 SP2 (X86 version for my particular instance), or the hotfix will not install. It will produce an error stating that the expected product version was not found on the system.

    1. I applied the fix and Outlook2010 reported that we already has the fix. But the issue is still there.

  53. I have noticed that I get these errors everytime I try to sync with someone who has a private appointment in their Calendar. Don’t know if the hotfix posted earlier would fix hide the warnings

  54. Still going on this? Any soltuion? I have the same issue with Outlook 2016 and Office 365.
    I think this has something to do with multiple devices working with the same mailbox/calender.

  55. Do you How to Remove the Sync Issues Folder in Outlook 2003 as ‘Not formed in NEO folders’ by catching the following steps: Go within NEO to the Outlook Folder Tab. Detect and right-click the clash folder. Facing problems in sync issues folder in outlook known more call us +1-844-872-1287 |

  56. 9 years after the original post and I came across this article. Seems this is a problem to span the decades and from on-prem to cloud. We have O365 with Outlook 2016 for Business and have this problem. Some users have their mailboxes filled up with 1 message, 4000 times – to the point where the mailbox is now full. Messages that land in the conflicts folder don’t seem to have any pattern and its a random occurrence.

    MS Support just told me to do the registry “fix” – EnableConflictLogging set to 0. After reading this, I am not feeling so lucky.

      1. Haha, no kidding! It looks like all our mailboxes have some conflicts but a handful are the ones going crazy and filling up. Don’t suppose someone has seen this in O365 and found a fix other than turning off cached mode (which does work).

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s