Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
If Outlook says that it's performing a data check each time it starts, that's an indication that it's not closing properly and the data file is still open when the process is killed, leaving it in a potentially inconsistent state. The most common cause of this is a misbehaving add-in. Use the Processes tab of Task Manager (press Ctrl+Shift+Esc to start it) to make sure OUTLOOK.EXE isn't running, then start Outlook in safe mode: hold Ctrl when you start it or enter
outlook.exe /safe
including the space in a command prompt windows or in the Open field of the Run dialogue (WinKey+R). If Outlook behaves normally when you start and stop it multiple sequential times in safe mode, then you're fairly assured it's an add-in. Start it normally, then use the Add-In Manager (File>Options>Add-Ins) to disable all your add-ins. Start reenabling them one at a time, stopping and restarting Outlook between each test until you find one that appears to cause the problem.
Brian Tillman [MVP-Outlook]
https://mvp.support.microsoft.com/profile/Brian.Tillman
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