Outlook Build 16.46 and earlier crashes soon after launch
Page Last Updated: June 6, 2021 @ 4:51pm Pacific Time

Problem
Users who have Outlook for Mac Build 16.46 and earlier may experience the app crash soon after launch if their mailbox is in Office 365.

Cause
A change to the Exchange Online servers started rolling out on May 24 - this has exposed a bug in older versions of Outlook for Mac.

Fix
Users need to update to Outlook for Mac Build 16.47 or later. Ideally, users should update to the latest production build of Outlook, which is 16.49 - however, a minimum of 16.47 is required to prevent the crashing behavior.
Download Outlook for Mac 16.47 Update Package or Download Outlook for Mac 16.49 Update Package

Support Article
An official support article has now been posted here.

How to identify if a user is hitting this problem
When Outlook crashes the Error Reporting window will appear. Clicking the 'More Information' button will show the crash log. A StackHash value of 45f9b64bc287c113-dm_1_bk positively identifies this bug.

Microsoft Error Reporting log version: 2.0

Error Signature:
Exception: EXC_BAD_ACCESS
ExceptionEnumString: 1
Exception Code: KERN_INVALID_ADDRESS (0x0000000000000000)
Date/Time: 2021-05-28 14:51:37 +0000
Application Name: Microsoft Outlook
Application Bundle ID: com.microsoft.Outlook
Application Signature: OPIM
Application Bitness: x64
Application Version: 16.44.0.20121301
Crashed Module Name: OutlookCore
Crashed Module Version: 16.44.0.201213
Crashed Module Offset: 0x00000000000d239a
Blame Module Name: OutlookCore
Blame Module Version: 16.44.0.201213
UnsymbolicatedChecksum: 04AC86A2D279270448E1FF202E4F1961
Blame Module Offset: 0x00000000000d239a
StackHash: 45f9b64bc287c113-dm_1_bk
Application LCID: 1033
Extra app info: Reg=en Loc=0x0409
Build Type: Release
Crashed thread Stack Pointer: 0x_00007000019f6cc0
Crashed thread: 1