First of all, I ran the update yesterday night and instead of rebooting I chose the reboot later option and shut the computer down instead. That's how I always do it when an update requires a restart and I don't feel like rebooting. Usually this works since there's no difference between a reboot and a shutdown + start in the morning. Why the DOpus installer has a problem with that I don't understand. I think it has done that the last time as well. In the morning after startup it offers to install the update again. It's still running the previous version.
Small nitpick, but this time I am also getting an error when trying to run the update.
It shouldn't matter with the Opus installer either. As you say, there's no difference between a shutdown and a reboot, at least at the level that the installer works. I do a shutdown after installing updates on machines I'm not going to keep using all the time for the same reasons you describe, and haven't had a problem. (At least, not since the Win9x or XP days.)
"Catastrophic Failure" is the English string for the generic E_FAIL error code, which really just means something failed and didn't return a more meaningful error. (It's unfortunate that the error text is so hyperbolic, and that E_FAIL is used so often by various components and the OS itself.)
The While installing Opus, you get an error message similar to this... part of this guide may fix things for you:
Rebooting again is also worth a try, in case something to do with the old update is still pending.
Antivirus is worth checking in case it is blocking the new files being written. That could be the root cause of all the problems here, and some antivirus will treat new versions of programs with unnecessary suspicion.
