After already having experienced exactly the same before I used an OS backup file and went back to Cubase Pro 9.5.21.
After that Cubase 9.5.21 worked ok again.
As Steinberg and users are recommending here the next thing I did was: I installed all the Windows 7 updates available.
Then I tried again to update to Cubase Pro 9.5.30.
The same failure as before:
The Installation of eLicenser Control Software gets hung up saying:
The green bar reaches almostly it’s end, just almostly. Exactly there the setup gets hung up, as you might see here:
No different issue, most likely because I moved some files out of the program folder.
My point was more that a repair would be a good thing to try.
Windows programs/apps (sorry not using Windows in English I am guessing) find the entry
Steinberg Cubase 9.5 click on that and Edit, then next and then choose repair.
After it is finished you could try the 9.5.30update again
I finally could resolve my issue going back to an older OS-partition image and then updating to v9.5.30 as admin. Worked flawlessly. Don’t know, what has been the reason for my described problems, but creating weekly images of the OS-partition is simply the best choice for any serious user.