You run a saved prompt and receive the following response:"You asked for a summary of...

Comprehensive and Detailed 150 to 200 words of Explanation Microsoft AI Business professional documents:

When Microsoft 365 Copilot cannot access a referenced file, it may return a message indicating that the file is empty, corrupted, or cannot be processed. In many cases, this message appears when the user does not have sufficient permissions to open the file in SharePoint, OneDrive, or another Microsoft 365 location.

Copilot operates within the Microsoft Graph security boundary and strictly respects user permissions. If a saved prompt references File.docx but the user no longer has access to it—due to permission changes, file relocation, or removal—Copilot cannot retrieve the content for grounding. As a result, it cannot analyze or summarize the file and returns a processing-related error.

Not scheduling the prompt is unrelated to file processing. Running from a web or desktop app does not affect file readability. Using a different agent does not typically cause a file-format processing error.

Therefore, the most likely cause is that you do not have access to the file.