Microsoft has shared a temporary fix for a known issue preventing Microsoft 365 customers from replying to encrypted emails using the Outlook Desktop client.
This confirms customer reports regarding these issues when using the classic Outlook clients shared on Microsoft’s community website in recent months.
According to online reports, reinstalling Outlook or creating a new profile for the impacted email account fails to address the issue.
As Redmond explained in a Thursday support document, the issue only affects Microsoft 365 customers on Current Channel Version 2402 (Build 17328.20142) and higher, released on February 28.
It also impacts only those who must respond to emails encrypted using Office 365 Message Encryption (OMEv2), now known as Microsoft Purview Message Encryption.
Affected customers will receive error messages stating, “Microsoft Outlook was not able to create a message with restricted permission” when trying to reply to messages using Microsoft encryption.
Official workarounds available
As a temporary fix, Microsoft says you can still reply to encrypted emails using the new Outlook or Outlook Web Access (OWA).
If you can only use the Outlook Desktop app to reply to encrypted emails you receive, you can revert to the last working build.
To do that, you will have to type Command Prompt in the Windows search box, right-click Command Prompt, and click Run as administrator.
Next, you have to paste the following commands in the Command Prompt window and hit Enter after each:
cd %programfiles%Common FilesMicrosoft SharedClickToRun
officec2rclient.exe /update user updatetoversion=16.0.17231.20236
Last month, Microsoft also rolled back a fix for an Outlook issue caused by the December Outlook Desktop security updates triggering incorrect security alerts when opening ICS calendar files.
Recently, the company also resolved another known issue causing Outlook desktop clients to stop synchronizing with email servers via Exchange ActiveSync and a bug causing connection problems for Outlook.com users on both desktop and mobile email clients.