Microsoft confirms that a new bug can cause Classic Outlook to crash on startup

Neowin reports that an older version of Microsoft's Outlook mail app has been hit by a new bug that simply causes the program to crash on startup. Microsoft writes on its support page that the bug affects Classic Outlook 2407 Build 17830.20138 or later, and is due to the fact that the server rules for the Microsoft 365 account may be corrupted.

Read also: Our guide to Outlook in Microsoft 365

To make sure that this is the latest bug, and not another issue, that is causing Outlook to crash, you can open it. log book Search for event 1000 or event 1001 and see if the following text is present:

Error bucket 1620625936954482602, type 4
Disabled application name: OUTLOOK.EXE, version: 16.0.17830.20138, timestamp: 0x66aaad8c
Invalid module name: ucrtbase.dll, version: 10.0.22621.3593, timestamp: 0x10c46e71
Exception code: 0xc0000005
Error offset: 0x0000000000005137c
Error process ID: 0x0x5A00
Application crash start time: 0x0x1DAE741D3515015
Path of the disabled application: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

Read also: Tampering with some Gmail accounts in Outlook

Microsoft says there are several ways to work around the error. You can either clear the rules in the Outlook app by typing Outlook.exe /cleanrules In the program Leadsby creating a new Outlook profile, or by signing in to the web version of Outlook and removing all rules for your account.