Unable to open .rpmsg files with Microsoft Purview Information Protection viewer

Hello everyone,

I'm facing an issue trying to read an encrypted message and would appreciate your guidance.

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Summary of the Issue:

I received an encrypted message (.rpmsg file) in Gmail. I am unable to open it either through the web-based "Read the message" button or by using the Microsoft Purview Information Protection desktop viewer.

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Background & Steps Taken:

1. I received an email in my Gmail account protected by Microsoft Purview Message Encryption.
2. I clicked the "Read the message" button within the email.
3. I successfully authenticated using my Google account and a one-time passcode.
4. However, the web page displayed an error: "Sorry, we can't display your message right now."
5. As an alternative, I downloaded the message.rpmsg file and tried to open it using the Microsoft Purview Information Protection viewer on my desktop, as suggested by Microsoft Support documentation.
6. This also failed with the following error message: "Error: Microsoft Purview Information Protection does not support labeling for the current file format. The file may be in a previous Office format."

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Additional Information:

I found the following troubleshooting article, but I was unable to implement the suggested solutions due to security and permission restrictions on my company-issued PC.

https://learn.microsoft.com/en-us/troubleshoot/microsoft-365/office-message-encryption/cannot-display-message

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My Questions:

1. Is the Microsoft Purview Information Protection viewer not capable of opening .rpmsg files? The error message seems to suggest a format incompatibility.
2. Are there any other methods I can use to read the contents of this .rpmsg file, especially considering the restrictions on my corporate PC?

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Any help or insight you can provide would be greatly appreciated.

Thank you.

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*This was written with the assistance of AI.