DO12: Puzzling installation and restoration behaviour

I have no idea of the significance of this, but I'll report it in case it's a clue about something. My desktop has been at the menders, and is now at the wreckers, with no replacement yet, so I have kept out of DO12 until today, when I am installing it on my 64-bit HP ProBook Notebook:

  • I backed up my notebook DO11.18.0.0 configuration once again.

  • I installed DO12.0.4.0 without uninstalling DO11, then rebooted.

  • No configuration wizard appeared, but the visible toolbars were presumably the factory-reset toolbars.

  • I installed my new Beta Certificate and did a very, very small tour of these toolbars. My various global shortcuts seemed to be working OK.

  • I restored my DO11 configuration rather than fiddle about with the toolbars.

  • DOpus did not re-launch. The link file did nothing. Clicking on the .exe file in C:\Programs also did nothing.

  • Programs and Features still showed DOpus installed, so I uninstalled it there, with no additional file deletions, and rebooted.

  • I installed DO12.0.4.0 again. No reboot required.

  • This time I was invited to run through the setup configuration steps, but I cancelled out.

  • I changed to shared configuration, which I always use (I didn't look at that setting the first time).

  • I re-launched DOpus, then restored my previous DO11 configuration once again.

  • This time DOpus started up again with my DO11 configuration, and with no problems.

  • I installed my new Beta Certificate, and order is restored to the kingdom.