OST file corruption ?

Hi @Mounia Hlimi

Having your emails fail to sync properly across folders is incredibly frustrating. After rebuilding an Outlook profile, seeing the main Inbox update while subfolders stall with outdated messages is a classic sign of synchronization trouble. While you have already tried restarting, updating, and re-adding the account, subfolders and recent emails failing to sync can actually be caused by multiple reasons, such as background synchronization limits, network drops, or a corrupted local cache.

If we suspect the OST file might indeed be corrupted, let's first try the steps below to rebuild it. Before proceeding, could you please provide a little more information to help narrow this down?

• What type of email account are you using (e.g., Exchange, IMAP)?
• If you check Outlook on the web, do the subfolders and recent messages display completely?

If you are using an Exchange account and everything shows up fully on Outlook Web, please try the following steps to force a fresh sync and rebuild the OST file:

Close Outlook completely > Navigate to where your data file is stored (you can press Win + R, type %localappdata%\Microsoft\Outlook, and press Enter) > Rename your .ost file (e.g., to .ost.old) or delete it. > Restart Outlook. It will create a fresh OST file and re-download your data directly from the server.

Note: Please also go to File > Account Settings > Account Settings, select the email account experiencing the issue, click Change, and make sure to move the download slider all the way to the right.

Let me know how it goes or if you need any further assistance!

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