Regarding 1.
On the PCs where I have newly installed wfview (2 PCs), there is no problem.
However, on the PCs where I previously installed the test version (2 PCs), the problem occurs even after deleting the files.
Yes that will be because it still retains the config. I am looking at an option to remove the config, but if you are comfortable with Registry editing, simply delete the key:
Computer\HKEY_CURRENT_USER\Software\wfview
Obviously be very careful when editing the registry and as all of the Microsoft docs say, always take a backup before making any changes (I’m sure we all do!)