Microsoft Resolves Outlook Bug That Blocked Encrypted Emails
▼ Summary
– Microsoft has resolved a bug that prevented Microsoft 365 users from opening “Encrypt Only” emails in classic Outlook after a December update.
– The issue caused encrypted messages to appear as an unreadable `message_v2.rpmsg` attachment instead of displaying their content.
– A fix is now available in the Beta Channel and will roll out to Current Channel users in February.
– Temporary workarounds include senders using a different encryption method or users reverting to an older, unaffected Outlook build.
– This follows a series of other recent bugs Microsoft has addressed in classic Outlook, including problems with drag-and-drop, CPU spikes, and crashes.
Microsoft has successfully deployed a fix for a problematic bug that was preventing users of the classic Outlook application from accessing emails protected with “Encrypt Only” permissions. This issue, which emerged after a December software update, left recipients facing an unreadable `message_v2.rpmsg` attachment instead of the intended message content, effectively blocking communication. The resolution is now being distributed, marking an end to a significant disruption for Microsoft 365 subscribers relying on this specific encryption method.
The problem specifically affected users who had installed Current Channel Version 2511 (Build 19426.20218). When attempting to view an affected email, individuals encountered a frustrating prompt in the Reading Pane stating, “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.” Following this instruction did not resolve the access problem, leaving the encrypted messages inaccessible.
According to an updated support bulletin, the corrective update is currently available for users in the Beta Channel. A broader rollout is scheduled for February, targeting the Current Channel and Current Channel Preview with Build 19725.20000. For organizations and individuals unable to update immediately, Microsoft has outlined two temporary solutions to restore functionality.
The first workaround involves a change in procedure for the sender. Instead of applying encryption through the File dialog, the person composing the email must select the Encrypt option located under the Options ribbon within Outlook. This alternative method bypasses the bug that corrupts message display for the recipient. The second, more technical fix requires users to manually revert their Office installation to a previous, unaffected build. This process involves closing all Microsoft Office applications and executing a specific command from an elevated Command Prompt window.
This encryption bug is the latest in a series of challenges for the classic Outlook client. In the past year, Microsoft has addressed several other disruptive issues, including malfunctions with email drag-and-drop functionality following Windows updates and incidents causing severe CPU usage spikes during message composition. The development team has also previously resolved crashes that occurred when opening emails or starting new messages, and provided a workaround for errors related to opening encrypted emails.
The company recently had to issue an emergency, out-of-band Windows update to tackle a separate critical bug that caused the classic Outlook application to freeze completely. These recurring issues highlight the ongoing complexity of maintaining compatibility and security within the extensive Microsoft 365 ecosystem, especially for the legacy classic Outlook platform alongside newer web and subscription-based versions.
(Source: Bleeping Computer)
