Can you

• open Windows File Explorer
• navigate to your ProSeries installation
• click into your /common directory

Do you see a file called ExcellPresentation.xls.bak?  If so make a copy of it, named ExcelPresentationTest.xls, and then double click it.  What happens?  You should get our template file.. i'm wondering if you get any warnings or errors.

If it opens fine, what happens if you try to view the client presentation from within ProSeries (Open a Client, Choose Tools -> Client Presentation -> View Client Presentation in Excel...)?

Finally, what is the exact version of excel? On my computer, if I click on the Excel "Account" link I see I'm on "Microsoft Office Professional Plus 2019", with Excel Version 2101 (Build 13628.20448)