Classic Outlook crashes on reply and forward

Last Updated: January 17, 2025

ISSUE

After updating to Version 2412 (Build 18324.20168) classic Outlook may crash when starting a new email, or when replying or forwarding an email. 

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:   
 
Faulting application name: OUTLOOK.EXE, version: 16.0.18324.20168, time stamp: 0x677828da 
Faulting module name: OUTLOOK.EXE, version: 16.0.18324.20168, time stamp: 0x677828da 
Exception code: 0xc0000005 
Fault offset: 0x0000000001a7c02a 
Faulting process id: 0x0xFD0 
Faulting application start time: 0x0x1DB65D0FD0B9857 
Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE 
Faulting module path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

STATUS: WORKAROUND

This issue is fixed for Current Channel with Version 2501 Build 18429.20000 estimated to be released January 28, 2025.

To work around the issue, you can revert to the prior Version 2411 (Build 18227.20162):

1. Open a Command Prompt in Administrator context.

2. Type or paste the two commands into the Command Prompt window and press Enter after each:
   
   cd %programfiles%\Common Files\Microsoft Shared\ClickToRun
   
   officec2rclient.exe /update user updatetoversion=16.0.18227.20162

3. To prevent Office updating back to the latest build you can turn off updates by selecting File > Office Account > Update Options > Disable Updates.

4. Put a reminder on your calendar for February 11th to re-enable updates. Or, check back on this Known Issue in case it is addressed sooner.

The builds to revert are taken from the Update History page, Update history for Microsoft 365 Apps (listed by date).

Additional Resources

How to revert to an earlier version of Office

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See Also

Fixes or workarounds for recent issues in classic Outlook for Windows