Apologies, I discovered the error was mine regarding being unable to return to the gallery I was working on. When I re-installed Pro, after deleting all the files, there was no desktop shortcut generated, and I couldn't find a way to create one (the software does not seem to allow this from the taskbar), so I launhed Air instead, from the directory, which then launched Pro. But there was no Images option on the menu. So I took a chance and restored the shortcut from trash and it worked and I got the full menu. Now I can go back to the gallery I'm working on. Problem solved. Sorry to have caused confusion.
I should probably mention I'm still using Windows 8 on this computer. Maybe it works differently in Win 10.
As an aside, when I upgraded to Pro from Lite, the branding stayed in the lower right corner, despite the interface claiming I was using Pro. That was when I realized there were issues with the directory path (and a possible conflict with Lite), so I deleted both versions and reinstalled Pro and moved the gallery to the same directory as the software. Live and learn.
Thanks for the Linux Air link. Will try and get that set up next.