I have a client experiencing the same issue with 4 out of 10 users. I did notice errors in the event log stating Insights was crashing around the same time as the ucrtbase.dll error on the workstations with the issue. I didn't add the Sophos exclusion, but removed the Insights add-on from Outlook for 2 of the users to see if it makes a difference.
Microsoft Outlook Application Crash due to UCRTBASE.DLL
Windows 10 Build 2004
Outlook crashes intermittently and generates the following Application Event Log error.
Event 1000, Application Error (11:06AM, 12/7/2020) Faulting application name: OUTLOOK.EXE, version: 16.0.13426.20308, time stamp: 0x5fc6ea9b Faulting module name: ucrtbase.dll, version: 10.0.19041.546, time stamp: 0x73123758 Exception code: 0xc0000409 Fault offset: 0x0009edbb Faulting process id: 0x41c0 Faulting application start time: 0x01d6ccaedccaa9fa Faulting application path: C:\Program Files (x86)\Microsoft Office\root\Office16\OUTLOOK.EXE Faulting module path: C:\WINDOWS\System32\ucrtbase.dll Report Id: f8791f7b-faf7-452a-8ff2-7268662a6db2 Faulting package full name: Faulting package-relative application ID:
I have run SFC /SCANNOW
I have completely uninstalled and reinstalled Microsoft Office 365
Here are the properties of the failing file:
Windows for home | Windows 10 | Performance and system failures
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69 answers
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Anonymous
2021-01-28T03:30:53+00:00 -
Anonymous
2021-01-26T17:07:29+00:00 Keep up the good work! Like to hear from you if you've found the sub-component which is causing Outlook to crash. I didn't go that far, but it would isolate the exception to a minimum.
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Anonymous
2021-01-26T16:53:59+00:00 We added the Microsoft Outlook exclusion for the Exploit Mitigation component as well and have not had any crashes since then. I know many others have submitted tickets to Sophos regarding this issue, but I'll be creating one just to emphasize the need for a more permanent solution.
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Anonymous
2021-01-26T14:57:50+00:00 We have applied the Outlook exclusion, and no crashes.
We have many clients and this only affects one, they work in Insurance and run Act! and Acturis. They are our only client running those, anyone else using either? They both have plugins to Outlook but as the crashes happen in safemode I had discounted 3rd party addins.
None of my clients use those applications. I think it is just something with the Sophos Mitigation component messing with Outlook.
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Anonymous
2021-01-26T14:45:44+00:00 We have applied the Outlook exclusion, and no crashes.
We have many clients and this only affects one, they work in Insurance and run Act! and Acturis. They are our only client running those, anyone else using either? They both have plugins to Outlook but as the crashes happen in safemode I had discounted 3rd party addins.