Microsoft is investigating a newly identified issue that prevents users of the classic Outlook client from opening encrypted emails sent by other organizations.
The company confirmed the problem in a recently updated support document, noting that the bug affects customers across all Office release channels.
According to Microsoft, users attempting to access such emails may encounter the error message: “Configuring your computer for Information Rights Management.” The glitch impacts OMEv2 (Office Message Encryption version 2) messages when sent across different tenants, creating disruptions for enterprise communication.
Temporary workaround provided
While the root cause is still under review, Microsoft has issued a temporary fix. Impacted organizations can either exclude external users from Conditional Access policies or enable cross-tenant settings that allow authentication tokens to be trusted between Entra tenants.
The company recommends the second option as the simpler solution. Administrators can enable cross-tenant access by navigating to the “Inbound access settings – Default settings” page in the Microsoft Entra admin center, selecting “Trust settings,” and then enabling “Trust multifactor authentication from Microsoft Entra tenants.”
Microsoft cautioned, however, that this workaround only ensures encrypted emails sent from an organization can be opened by others.
To access encrypted messages received from a different tenant, the sending organization must also apply the same configuration.
Ongoing investigation
The Outlook and Purview teams are currently working on a permanent resolution.
Microsoft has assured customers that updates will be shared once more information is available.
This is the latest in a string of Outlook-related bugs addressed by Redmond (a global headquarter of Microsoft) this year.
In June, the company resolved a crash affecting the classic Outlook client when opening or composing emails. Later, in August, it mitigated an Exchange Online issue that blocked mobile users relying on Hybrid Modern Authentication.
With encrypted communications becoming central to enterprise security, a swift resolution will be crucial to ensure seamless cross-tenant collaboration.
