Hi @Frank Bell
Thank you for reaching out to Microsoft Q&A forum.
Based on the information you provided, I understand that after reinstalling the software/OS on your MacBook Air yesterday, you are unable to install Microsoft 365 using your account.
Please follow the steps below to troubleshoot this issue:
- Verify License and Download Directly
First, please ensure that your Microsoft 365 license is still active and assigned to the account you are logging in with. Instead of using the Mac App Store, I recommend downloading the installer directly from the Microsoft portal:
Reference: Download and install or reinstall Microsoft 365 or Office 2021 on a PC or Mac
- Run the License Removal Tool
If you are still unable to install or sign in, please try removing any previous license credentials that might be causing a conflict.
- Please download and run the License Removal Tool following the instructions in this document: How to remove Office license files on a Mac
- After running the tool, restart your Mac and try installing/signing in again.
If neither of the steps above resolves the issue, please check your Private Messages. I have sent you a message there so you can provide a screenshot of the error message you are seeing, which will help me investigate further.
Please let me know if you have any updates!
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