Hello everyone, I'm facing a unique problem with one user in our company regarding Outlook and IMAP. The scenario involves a Windows 11 installation (version 25H2) that's fully updated, running Office 2019, and managing an IMAP mailbox with a local OST size of over 37 GB and more than 400,000 items to index. The user's Windows Search keeps triggering full index rebuilds, which has been happening since August. We've tried everything from creating a new Outlook profile to reinstalling Windows entirely, yet this issue remains persistent for this particular user, while others with IMAP mailboxes don't experience these rebuilds. I've gone through all sorts of checks and configurations, but I'm stuck on why this is happening exclusively for them. Before I move the user to Microsoft 365 or make significant server changes, has anyone else encountered a similar situation where only one IMAP user's OST catalog keeps resetting? What other workarounds might exist aside from common suggestions like switching email clients? Thanks!
2 Answers
Have you checked the Windows Search logs in the Event Viewer? I had a similar situation where the SYSTEM account lost permissions, which led to some strange Search behaviors. It might help you identify any underlying issues.
You could try closing Outlook and then deleting the existing OST file to let it rebuild while using the same profile, instead of creating a new one like you've already attempted. Just remember to back up your OST first!
Definitely copy the OST to a USB drive first. It’s best to hold onto it until you're sure the rebuild worked!