Hi Rhonda Heenan
Thank you for reaching out to the Q&A Forum.
Based on your description, I would like to share some information from my research that I hope will be helpful.
If you are normal user
According to my understanding, because IRM applies strict security encryption and permission rules (such as preventing printing or copying content), the web-based versions of Excel and Word often cannot enforce these security measures within a web browser environment. Therefore, the system blocks editing in the browser to maintain the security of the file.
To edit these files, you can try to use the desktop versions of the applications.
Open the file in the browser (where you see the error) > Look for the button that says "Open in Desktop App". The file will launch in the full version of Excel or Word installed on your computer, where IRM credentials can be verified securely.

If you are IT Administrator (or the owner of the SharePoint site, as there may be a setting they can toggle)
If a document is encrypted with specific limitations particularly if the "Edit" permission is granted but "Copy" or "Print" is disabled; Office Online often cannot render the file because the browser cannot guarantee those specific restrictions are enforced (ex: a browser cannot stop a user from using the browser's native print function).
You can try to check if IRM is enabled for the Office for the Web service.
- Go to the SharePoint Admin Center > Navigate to Settings > Classic settings page.

- Check the section "Information Rights Management (IRM)" and ensure "Allow users to preview documents that are protected by IRM" is selected.

If you try clicking "Open in Desktop App" and it still doesn’t work"the issue may no longer about the browser, it might be an authentication or permission issue on your computer.
To better understand your situation, could you please share some information:
- What happens when you click "Open in Desktop App"? Does it do nothing or show a blank screen? Or does it give a specific error code?
- Which account are you signed into in the Desktop App? You might be signed into Excel with a personal email (Outlook/Gmail), but the file is protected for their Work email. The accounts must match.
- What version of Office are you using? Go to File > Account > About Excel. If you are on a very old version, it might not support the newer IRM security protocols.
- Do you have "Edit" permissions?
Additionally, I hope you understanding that this forum is a peer-to-peer community, so while members can share advice and experiences only.
I hope this information helps and I look forward to your response!
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