Excel Power Query Editor --> New Source --> returns blank screen

In Excel --> Power Query Editor I want to select a new source. I can select any kind of new source, but I always get a semi-blank screen in return for any sources I might select (see picture below):

I have tried to reinstall Office. And. The problem was solved ... once. Then back to the same problem.

But. Excel-files that already is using Power Query tables works fine (which means I can use a colleages working Excel version to select a New Source...)

I run Windows 11,

and I use: Microsoft® Excel® for Microsoft 365 MSO (Version 2404 Build 16.0.17531.20120) 64-bit

I have no retwork issues. Further: no problems selecting "New Sources" using Power Query Editor in Power BI Desktop.

Any suggestions to resolve this issue?

Regards,

Hans Vestman