Good morning.
Run the Fix It and this time the update offered 15 important updates. None succeeded, 0x800B0100 and code 643

The Fix It told that:
> Service registration is missing or corrupt - fixed
> Windows Update error 0x80073712(2015-08-12-Y-08_01_10) - fixed
> Problems in installing newest updates - fixed
> Encryption service components not registered - fixed
and:
> Incorrect Windows Update environment variables - not found
> Some security settings are missing or have been changed - not found
> Check for missing or corrupt files - not found
> Windows update services not running - not found
(my translations again)
Btw, after every "repair round", the Windows Update tells that previous update checked/updates installed NEVER. This is maybe normal due modifications?