Why "Error! Check activation"?

I bought a book from Google Books and am also getting this error when I try to load it into ADE in Windows 10.  My first attempt at getting Support was to call Google.  They determined it was an ADE problem and referred me to Adobe.  And the advice here is that I have to go edit the registry!

There seems to be a recent flurry of these complaints, and my question is: Why?  Why is there a problem the solution to which requires me to edit the registry and re-authorize the computer?  Is there a bug?  And if so, when will it be patched? 

This isn't a trivial fix.  Have these instructions actually worked for anyone?