Outlook syncing issue - emails return from folders to inbox

Shadowstripe 0 Reputation points
2026-09-17T09:07:45.6366667+00:00

I have my work email on the Outlook app on my PC laptop and on my iPhone. I'm able to send and receive emails on both, but recently any changes I make in Outlook revert back after a while: I read emails, action them, and move them to various folders. Then later I open the mail app on either device and all those emails are back in my inbox, most of them marked as unread.

Outlook | Windows | New Outlook for Windows | For home

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  1. AI answer

    2026-09-17T09:08:08.6966667+00:00

    This pattern usually points to a sync problem between the Outlook client and the mailbox. A practical way to narrow it down is to check whether the mailbox itself is correct on the web, then refresh the local Outlook cache.

    1. Check the mailbox in Outlook on the web.
      • If the messages stay moved there, the mailbox is likely fine and the issue is with sync on the PC or phone.
      • If the messages also return to Inbox there, the problem is happening at the mailbox side.
    2. On Outlook for Windows, resync the affected folder.
      • Right-click Inbox or the folder where the problem occurs.
      • Select Properties.
      • Select Clear Offline Items > OK.
      • On the ribbon, select Send/Receive > Update Folder.
      • This forces Outlook to download the folder contents again.
    3. If the problem is specifically with Inbox in Cached Mode, clear and resync Inbox.
      • Right-click Inbox > Properties.
      • On the General tab, select Clear Offline Items.
      • Confirm the prompt that the data was removed from the .ost file.
      • Select OK.
      • Select Inbox in the navigation pane and press Shift+F9 to force resynchronization.
    4. If the issue continues, rebuild the OST cache on the PC.
      • This is a stronger reset of Outlook’s local cache.
      • Risk: local data not present on the server can be lost.
      • Close Outlook first.
      • Go to C:\Users\<username>\AppData\Local\Microsoft\Outlook.
      • Rename the OST file to .old.
      • Start Outlook and wait for the mailbox to fully resynchronize.
    5. For the iPhone, remove and re-add the sync partnership if the problem appears only on mobile.
      • In Outlook settings, go to Settings > General > Mobile devices.
      • Delete the device partnership.
      • Save.
      • Power off the mobile device, restart it, and sync the mailbox again.

    If messages are visible correctly in Outlook on the web but keep reappearing only in the apps, start with steps 2 and 3 on the PC before changing anything on the phone.

    References:

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  2. SD - IA 180.3K Reputation points Independent Advisor
    2026-09-17T09:53:46.5066667+00:00

    Hi,

    1. Do you know how it is configured - using POP or IMAP?

    Let me try suggesting Outlook reset.

    Press Windows + R, type %localappdata%\Microsoft, and press Enter.

    • Delete the Olk and OneAuth folders.
    • Restart Outlook.
    • This only removes temporary Outlook data that will be recreated automatically.
    • Try reconfiguring, then open New Outlook and check.

    See if the issue goes away after these steps.

    I look forward to hearing from you to get the results of the troubleshooting.

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