Not sure why it happened. You will need to reconfigure the paths.
Thank you, Erel.
I have already reconfigured the paths. Also, re-established the Private Sign Key and the IDE settings. The recent project list cannot be re-constructed, but that is not important.
The only clue is that there had been a recent restart by Windows 8.1 - it affected my Norton Internet Security to the point that I had to have a tech from Symantec remote log in and check my environment. Obviously, everything points to the Windows restart, but I am almost certain that B4A was not running.
Anyway, a little time lost, but no consequences.
Best regards.
Sandy