Microsoft Outlook: Here’s a workaround for slow startups

If you’re a Microsoft 365 subscriber experiencing Outlook freezes at startup, there’s some good news on the way—Microsoft’s not only aware of the issue and working on a fix, but it has a workaround to try, too.

As Bleeping Computer reports, this problem affects Microsoft 365 users who sync their Outlook data files between their local PC and the cloud. When starting the app, it may act slow or even outright freeze; in airplane mode, you might also see an error message of “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” when trying to open the program.

Some users have been able to get into Outlook by quitting the misbehaving app and then opening it again, but Microsoft is currently suggesting a better workaround via Outlook’s Account Settings. In the Exchange Account settings, choose More Settings > Advanced, then check the box for Turn on shared calendar improvements. (Having trouble finding that option? You can read the more detailed instructions in Microsoft’s support page on the issue.)

Microsoft says this startup problem is caused by a conflict in the app, where it’s unable to determine the default state of the cache, due to Office and non-Office MAPI apps making different calls on that status. The program then acts unresponsive or stall out. When new profiles are created, or the setting for shared calendar improvements is turned off, it can trigger this scenario.

In other news about Outlook, Microsoft recently announced that it will completely replace Windows 11’s native Mail and Calendar apps by the end of 2024. In its post detailing the transition, new PCs shipping with Windows 11 will reflect the switch beginning in early 2024. Access to the Mail and Calendar applications will remain available in the Microsoft Store app through 2024.