Hello,Bridget Baumgartner
Welcome to the Microsoft community!
I have realized that you want to install Office 2021 on Mac.
I would like to clarify with you that OfficeSetup.exe is the name of the Office installer for Windows, are you sending the Windows installer directly to the Mac computer?
The Office installer on the Mac has a long name. It's Microsoft_365_16.85.2.24052614_Home_&_Student_installer.pkg
This is the correct installation package. You can download the correct installer package by opening a browser on your Mac and logging into https://account.microsoft.com/services.
There is also a history of Office for Mac updates, which you can also download here.
Update history for Office for Mac - Office release notes | Microsoft Learn
I also want to remind you that the first time you log in, the license may not be verified, so you can't edit. If this is the case you can refer to the following steps.
I suggest you use Office license removal tool to renew your license.
- Download the license removal tool.
- Open the pkg file in your Mac's Downloads folder.
3. Select Continue and follow the prompts in the setup wizard.
- If you want to start removing the licenses, select Install. You may need to enter the password for your Mac's local administrator account.
When the licensing tool is complete, select Close.
- Now open an Office app and sign in to activate with the email account associated with your Microsoft 365 for Mac license. If you're working on troubleshooting, you might need to reinstall Office before you sign in.
Once you have activated the product, restart the computer and you can get back to work.
For more information, please visit this website: How to remove Office license files on a Mac - Microsoft Support
Please understand that our initial response may not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.
Feel free to post back if you need further assistance.
Thank you for your understanding and patience and I look forward to hearing from you.
Ryan - MSFT | Microsoft Community Support Specialist