How to Fix : Sync Issues (This Computer only)

Question

Hi, I have an Issus with Synchronisation, Outlook, run this every time. with many Issus Sink Logs.

What I should do?

Thanks

GB

Answer 1

Open one of the newest Synchronization Log messages and use its error code to choose the repair; the “This computer only” label by itself does not identify the underlying synchronization problem.

Check whether mail is actually failing to synchronize

1. Send yourself a test message and compare Outlook with your provider’s webmail.
2. In classic Outlook, select Send/Receive → Update Folder.
3. Open the folder list using Ctrl+6, expand the affected account, and open Sync Issues.
4. Open the newest log and note:
   • The complete error code
   • The affected folder
   • Whether it reports authentication, connection, or local-data errors

Outlook records synchronization problems for mail, calendar, contacts, tasks, and other mailbox folders in Sync Issues, so numerous entries do not necessarily mean that all mail has stopped synchronizing.^1^

If webmail and Outlook contain the same current messages, the visible Sync Issues (This computer only) folder is principally a local diagnostic-log folder. Do not delete the account or Outlook data file solely to remove that label.

Apply the repair matching the log

Error 80040600-501-80040600-560

Microsoft associates this specific “Terminated in error” message with possible OST cache corruption. Rebuild the OST as follows:^2^

1. Select File → Account Settings → Account Settings → Data Files.
2. Select the affected account and note the file’s full path.
3. Confirm that it is an .ost file, then close Outlook completely.
4. In File Explorer, browse to that location and delete or, more safely, rename the OST.
5. Start Outlook and leave it open while it recreates the cache.

Do not delete a .pst file: it can contain the only copy of locally stored mail, calendar, or contacts. The documented cache-rebuild procedure applies to an OST.

If rebuilding the OST does not resolve that specific error, create a test profile:

1. Hold Shift while starting Outlook.
2. Select Options → New.
3. Name the profile and add the email account.
4. Start Outlook with the new profile and allow synchronization to finish.^3^

Keep the old profile until any locally stored data has been verified or exported.

Gmail or Yahoo with 0x800CCC0E, 0x800CCC0F, or 0x80070057

For these specific accounts and errors, refresh the saved OAuth credentials:

1. Close Outlook.
2. Open Start → Credential Manager → Windows Credentials.
3. Under Generic credentials, find entries beginning with MicrosoftOffice16_Data:OAUTH2 that belong to the affected Gmail or Yahoo account.
4. Remove those entries.
5. Restart Outlook and sign in again.
6. Restart Outlook once more if synchronization does not begin immediately.

Microsoft reports that the related service issue was fixed on March 20, 2026, but stale credentials can still cause the same symptoms after a password change.^4^

Error 0x80004005: The operation failed

This was a server-side folder-update issue with a fix rolling out to Exchange server builds later than 15.21.0155.000. If an organization’s mailbox remains on an older server build and the impact is significant, contact Microsoft Support rather than repeatedly rebuilding Outlook profiles.^5^

If the log shows another error

Run the classic Outlook troubleshooter through the Windows Get Help application. These troubleshooters apply to classic Outlook, not new Outlook, and must run on the same Windows PC as Outlook.^6^

If further diagnosis is needed, provide the exact error code and several non-sensitive lines around it from the newest Synchronization Log. Hide the email address, server name, and account identifiers.

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References

1. my calendar events are not syncing properly with Exchange Online - Microsoft Q&A
2. Terminated in error found in Outlook Sync Issues log files
3. Create a profile in classic Outlook for Windows | Microsoft Support
4. Users get errors 0x800CCC0E & 0x800CCC0F synchronizing Gmail and Yahoo accounts in classic Outlook | Microsoft Support
5. Mailbox folders are not syncing with 0x80004005 error | Microsoft Support
6. Resolve Outlook for Windows issues with automated troubleshooting tools | Microsoft Support