Microsoft Office has identified a potential security concern

[Atom]

I have several PC's and have installed MS Office 365 on all of them. When I do a new install of Windows and Office, I copy my Personal.xlsb file which has all my macros to this folder: "C:\Users\Tom\AppData\Roaming\Microsoft\Excel\XLSTART". I also import my QAT customizations. Other time I've done this everything works normally, but this time when I try to run a macro I get a prompt about Microsoft Office has identified a potential security concern. If I click on enable, then I get the "Sorry, Excel cannot open two workbooks...". I tried uninstalling and reinstalling Office 365, but no luck. I only have a single Personal.xlsb file on this computer. It has dual bootable hard drives. One Win 11 and one Win 10. The Win11 one works ok, but the Win 10 one does not. I have identified this problem on a different Win 11 computer where I do not use Excel very often.

Thanks for any guidance.

Update: What I have found is if I edit the QAT and remove the macro and then replace it with the same macro, I do not get the error.