I'm helping a client with an Outlook issue on their Windows 11 Home system. They recently updated from version 24H2 to 25H2, and now, when they close Outlook in classic mode (Office 365), it hangs in the system tray saying "Outlook closing". Task Manager shows no subprocesses, and it appears to be running normally. They are using a POP3 email setup due to the sensitive nature of their mail, and they can't switch to IMAP. Sometimes when restarting Outlook, it fetches only recent emails, while other times it shows today's emails right away. The data file is around 220MB with a larger archive stored in OneDrive, and I've attempted various fixes, including repairing Office, running Outlook in safe mode, and adjusting OneDrive settings. Any advice would be appreciated, especially since the issue isn't consistent and the data migration will be time-consuming.
2 Answers
It sounds like the main issue is with the size of the PST file. Once it goes over 35GB, it can cause major headaches with Outlook. On top of that, OneDrive syncing can complicate things since it tries to back up the locked PST file whenever Outlook closes. What I recommend is splitting your emails into separate PST files by year. Just ensure those smaller files aren’t in a syncing folder with OneDrive. So first, back up the PST you have, use the SCANPST tool to fix any issues, and consider having a local backup solution instead of relying on OneDrive. This way, it won’t try to resync the entire file every time you exit Outlook.
You might be right! I’ll see if I can dig up an article to clarify that. But it’s still wise to keep those PST files small to avoid issues.
There’s a chance this could be linked to a recent Windows update; some users have reported similar freezing issues after the latest patches. Microsoft is aware and investigating. You might want to consider uninstalling the latest update temporarily to see if it resolves the issue.
Interesting! I noticed the problem started around the time of the latest update. I’ll give that a shot and see if it helps.
Thanks for the advice! Just to clarify, I thought the limit for Office 365 PST files was 50GB, not 35GB. Have you seen any official sources on that?