I just forced the update on one of my systems as follows:
Run command as admin (you know how
)
wuauclt.exe/updatenow
close the window and wait for WU to kick in.
Had to do it twice as the first time errored part way (server overload?)
I also cleared out the WU download directory beforehand as advised in several places, then rebooted: c:\windows\softwaredistribution\download folder.