Following a fresh full system reboot, I noticed that Live Update had not automatically updated virus definitions for over 1 hour. In checking the NAV history, it showed multiple Live Update cancellations due to incomplete downloading of a 90 MB virus definitions file.
So, I tried to do a manual Live Update, but the update just hung at the "Checking for Updates" stage. I tried to cancel the update, with no success. Live Update would not close. I then used Windows Task Manager to close NAV "Live Update", which generated a "Symantec Service Framework" error message, causing the entire NAV 2013 program to crash.
Because of the NAV 2013 program crash, I did another full system reboot, ran Manual Live Update to complete the new virus definitions file download/installation, and while doing so, NAV 2013 encountered Error 8504, 104, which could not be autofixed.
I never had any of these problems prior to upgrading to NAV 2013 20.2.0.19. I now seriously regret upgrading to this latest version, as the continued problems have become just to much tot deal with.