Outlook stops responding when you attach an email .MSG file

Last Updated: March 26, 2024

ISSUE

Outlook stops responding when you attach an .MSG file to an email.  The problem occurs whether you drag the .MSG file to the email or select Insert > Attach File. 

If you review the Event Viewer for Event 1000 or 1001, it has the following event details: 

• Faulting application name: OUTLOOK.EXE, version: 16.0.17328.20068, time stamp: 0x65c8cfd8

• Faulting module name: mso20win32client.dll, version: 0.0.0.0, time stamp: 0x65c8cc7f

• Exception code: 0x0152139a

• Fault offset: 0x000000000024047d

• Faulting process id: 0x0x507C

• Faulting application start time: 0x0x1DA69BB3A648DB0

• Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

• Faulting module path: C:\Program Files\Common Files\Microsoft Shared\Office16\mso20win32client.dll

STATUS: WORKAROUND 

The Outlook Team fixed this issue for Current Channel and Monthly Enterprise Channel by making a service change on March 14, 2024.  The code change to permanently resolve the problem is at Beta Channel in build 17515.15030+.  

Semi-Annual Enterprise Channel (Preview) is currently expected to be fixed in the April 9th Public Update.   

If you urgently need to mitigate the issue, use Outlook Web Access (OWA) or New Outlook to send emails that require .MSG file attachments. 

Alternatively, you can revert Outlook Desktop to the builds prior to the issue.  For SACP you could revert to Version 2308 (Build 16731.20550). Revert the Office M365 Click-to-Run installation to Version 2308 Build 16731.20550.  

To do this:  

1. Exit all Office applications.

2. Select Start. Type cmd in the Search box, right-click Command Prompt (or cmd.exe), and then select Run as administrator.

3. In the command prompt dialog window, type the following two command lines, pressing Enter after each command line: 

   cd %programfiles%\Common Files\Microsoft Shared\ClickToRun

   officec2rclient.exe /update user updatetoversion=16.0.16731.20550

4. When the repair is done, open Outlook and select File > Office Account.

5. Select Update Options and then Disable Updates.

6. Add an appointment on your calendar for after April 9th to check back to this topic to confirm the issue is fixed. If it is, re-enable updates by selecting File > Office Account > Update Options > Enable Updates.