Last Updated: August 16, 2024
ISSUE
After updating to Version 2407 Build 17830.20138 or higher you find that Outlook may unexpectedly close at start up. Outlook will also close if you test in Safe Mode.
You can confirm if this is the issue by looking at the Windows Event Viewer Application Log for crash Event 1000 or Event 1001, and the following event details: Fault Bucket 1620625936954482602, Type 4 Faulting application name: OUTLOOK.EXE, version: 16.0.17830.20138, time stamp: 0x66aaad8c Faulting module name: ucrtbase.dll, version: 10.0.22621.3593, time stamp: 0x10c46e71 Exception code: 0xc0000005 Fault offset: 0x000000000005137c Faulting process id: 0x0x5A00 Faulting application start time: 0x0x1DAE741D3515015 Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE
This issue has been found to occur if the server-based rules for the M365 email account are corrupted or that Outlook cannot process.
STATUS: WORKAROUND
To work around the issue, do the following:
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Run Clean rules command line to remove the client and server rules.
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Close Outlook.
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Right-click the Windows Start button and select Run.
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In the Run box paste: Outlook.exe /cleanrules.
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Select OK.
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Create a new Outlook Profile, if necessary. For more information, please go to Create an Outlook profile.
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If you still have the issue, please go to Outlook Web Access and manually remove any rules.
For additional insight and questions, please see this forum thread, I very recently started having Outlook crash due to ucrtbase DLL.
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