Outlook stops opening .msg and .oft template files

Last Updated: May 11, 2020

ISSUE

Outlook for Office 365 fails to open .msg and .oft template files when Outlook is running. If Outlook is closed the files will open. The issue occurs after installing the Windows Updates listed below.

Original Update	Replaced by
Windows 10, version 1909 KB4554364	KB4549951; KB4550945
Windows 10, Version 1903 KB4541335	KB4554364;KB4549951;KB4550945
Windows 10, version 1809 KB4554354	KB4549949;KB4550969
Windows 10, version 1803 KB4554349	KB4550922;KB4550944
Windows 10, version 1709 KB4554342	KB4550927

When this happens, a crash event is logged to the Windows Event Viewer Application Log:

Faulting application name: OUTLOOK.EXE, version: 16.0.11929.20648, time stamp: 0x5e5dcedb Faulting module name: OLMAPI32.dll_unloaded, version: 16.0.11929.20602, time stamp: 0x5e3b26c9 Exception code: 0xc0000005 Fault offset: 0x000be59e Faulting process id: 0x3acc

Other symptoms that may be related to this issue:

Opening .eml and .ics files may also fail to open and trigger the crash event.
mailto: links on a SharePoint page do nothing when clicked.
Some links may not be clickable and might be related to the mailto: links.
Sending emails directly from Word or Excel using the File -> Share -> "Attach a copy instead" may error with "Word couldn't send the email because of a MAPI failure: "Unspecified Error"".
Outlook Jump List Tasks may not be actionable

STATUS: FIXED

This issue is fixed in the following updates:

Current Channel, Version 2004 (Build 12730.20236).

Monthly Enterprise Channel, Version 2003 (Build 12624.20588), May 12th public update.

Semi-Annual Enterprise Channel (Preview), Version 2002 (Build 12527.20612), May 12th public update.

Semi Annual Enterprise Channel, Version 1908 (Build 11929.20776), May 12th public update.

Semi Annual Enterprise Channel, Version 1902 (Build 11328.20578), May 12th public update.

Fixes for Outlook 2013, Outlook 2016, & Outlook 2019 Perpetual Versions are anticipated for the June 9th public update.

STATUS: WORKAROUND

Until the fixed version becomes available it may be possible to mitigate the issues by disabling the Windows 10 User Experience Virtualization Service (UEV). You can test this workaround by opening Task Manager and disabling the UevAgentService on a workstation experiencing the issue.