The simplest fix for issues with anything under the WindowsSelfHost Registry Key is to simply delete the entire WindowsSelfHost Key. It will be rebuilt.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\WindowsSelfHost
Run the following commands in command prompt as administrator
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
Try WU once again.