Error 1603 after notices to upgrade Adobe Acrobat XI Pro to 11.0.12 - but I'm at 11.0.12!

I switched to a new computer quite some time ago, upgraded to Windows 10, reinstalled Adobe Acrobat XI Pro, and managed to update up to 11.0.12, but I keep getting notices to update to 11.0.12, the program tries to apply the update, and fails, with error 1603.  This happens roughly monthly. I cannot apply any higher update. (The highest on Adobe.com appears to be 11.0.15.) I have tried to apply the updates manually, but get the error.

Help! I dread reinstalling and having to reapply every update by hand.  Any suggestions that doesn't involve uninstalling and reinstalling?