I tried resetting to Factory Settings, and also run as Administrator. It still doesn't solve the problem for me.

I installed BIAB to a separate hard drive (and folder name).

I have notified pgmusic of this bug, and told them that the .chm help file can be used if I open it directly from File Explorer (or a shortcut icon). I also let them know that it was installed to a non-default location, in case that's an issue.

Thanks for your help!