I had the same problem, i had previously installed all the updates, but then my machien blue screened on startup so rolled back everything, this seems to have corrupted the file
c:\windows\softwaredistribution\datastore\logs\edb.log
all i did was delete the log file reboot and now windows is updating :)
Worked for me - but I had to do a couple extra steps. Windows had the file in use. I needed to boot up into safe mode (F7 or F8 - I forget which when booting - I tap alternately repeatedly - follow prompts to get to safe mode once it looks different than
the normal boot-up). Once in safe mode, I was unable to browse to this website, so I needed to make certain to WRITE DOWN the location of the log file.
To be on the safe side, I renamed it rather than delete it - so at worst case, I could rename back later - but it did not cause any problems).
Only down side: it seemed to have lost its history on what updates I had installed and when - but it was able to check for updates, and now it has a history. Thus it was only a minor item