Microsoft has confirmed a known issue that prevents recipients from opening encrypted emails in classic Outlook.

There is no fix available, but you can always revert to an older version.

Microsoft is looking into a newly identified issue in classic Outlook that prevents users from opening certain encrypted ...

A new Microsoft-issued software patch for Outlook (Classic) on Windows 11 inadvertently broke encrypted email support - ...

For now, Microsoft can only recommend using a complicated workaround as it preps a fix.

A new Outlook (Classic) update is preventing Windows users from opening encrypted emails. Microsoft confirms the bug and ...

PCWorld reports that Microsoft has confirmed a bug in classic Outlook version 2511 preventing users from opening encrypted emails. This issue significantly impacts business users and organizations ...