The problem is apparently my PC with Windows 10. It had the default app set for .RGT as Adobe.
So the only other app available was called Audio Shark. I did the free download. I can now see every .RGT file (and they are no longer Adobe), but they are called Audio Shark files.
When I double-click, it allows me to see the data, and it appears to be fine. However, I cannot use it in the Registration Manager program, in order to convert it to PSR S770.
Any thoughts? I am grateful, in advance, for your help.
Jim Duprey