A new Microsoft bug is preventing certain Outlook users from accessing encrypted emails

A new over-the-air (OTA) software patch from Microsoft, build 19426.20218 of the Outlook (Classic) Windows client, has inadvertently introduced a novel bug into the iconic email program: upon updating, users are reporting the inability to open ‘encrypt only’ emails through regular means (via TechRadar)

Upon updating to this bugged build of Outlook (Classic), attempting to open an ‘encrypt only’ email may result in an error message appearing on-screen. Rather than business as usual, text will appear within the app’s Reading Pain section that reads: “This message with restricted permission cannot be viewed in the reading pane until you verify your credentials. Open the item to read its contents and verify your credentials.” Opening the email then results in a null “message_v2.rpmsg” attachment file appearing, which can’t be read in-line.

Over on the official Microsoft support website, the company acknowledges classic Outlook’s newly-broken behavior, with the status section of the page writing: “The Outlook Team is investigating this issue for a fix. We will update this topic when we know more.”

Three workaround methods are available

You’ll need to rely on these stopgap solutions until Microsoft issues another Outlook patch

If you’re an active Outlook (Classic) user on Windows 10 or 11, and if the broken OTA code has already beaten you to the update punch, there are three main interim solutions available at your disposal. Firstly, Microsoft itself has published the following steps as a temporary fix:

1. Navigate to the Options tab within the main ribbon menu at the top of the screen, and then select the Encrypt option.
2. Next, tap or click on Do Not Forward.

If this doesn’t do the trick, Microsoft also provides a secondary workaround, which involves reverting to an older version of classic Outlook from before the issue arose in build 19426.20218. To roll back your software, follow these steps:

1. Save all your work and then close all running 365 Copilot / Office 365 applications.
2. From here, open an elevated Command Prompt (the Command Prompt in its elevated form is accessible via Windows Search > Command Prompt (Admin) or by right-clicking on the Windows logo button and selecting Terminal (admin).
3. Next, run the following command within the Command Prompt interface:

"%programfiles%\Common Files\Microsoft Shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.19426.20186 Lastly, as a final resort, you can consider switching to another Windows 11 email client for viewing incoming ‘encrypt only’ emails — at least until an official patch is pushed out to Outlook (Classic). Options include the main Outlook.com website, the new web-based Outlook app for Windows, as well as third-party options like Wino Mail, Mozilla Thunderbird, and Spark Mail.