Security News > 2023 > October > Microsoft fixes known issue causing Outlook freezes, slow starts
Microsoft has fixed a known issue affecting Outlook for Microsoft 365 users since June and causing slow starts and freezes as if Offline Outlook Data Files were syncing right after launch.
Error messages appeared, stating, "Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. The attempt to log on to Microsoft Exchange has failed."
These issues with Outlook freezing and experiencing slow starts would occur during cache re-priming, a process triggered when creating new profiles or disabling shared calendar improvements.
Microsoft has previously tackled various Outlook issues, including ones in April preventing Microsoft 365 customers from accessing emails and calendars, login problems in October 2022, and a bug causing Outlook to freeze and crash immediately after launch in August 2022.
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