i have tried the trouble shooter to no avail. WSUS runs but fairly quicklybefore saying 100% and giving an error message.
Then it looks like a trip into the command line and a run of SFC is in your near future. Failing that it's a reset of Windows.
SFC shows unfixable errors and refers me to a log file that I cannot find C:\Windows\Logs\COS\COS.log. Looks like a fresh install or a reset if that is any easier. I am doing this on a spare SSD used as a backup so if I bugger it up then I can just clone it back from my main one. I am using the backup drive at the moment which is now my C drive.
before you go nuclear on it... try this in an admin prompt: if that also throws a hissy fit then go nuts and reset/reinstaall, if it runs through to completion, restart and run SFC again.
You may want to backup your files and then just do a clean install. This usually irons out problems such as the one you've mentioned.