On two machine, I've tried to update MiKTeX. With both machines it tells, that initexmf fails. On the first machine, I only had to update packages, on the second machine a prior binaries update was necessary (which was successful). Attached you'll find a log, which tells
"C:\Programme\MiKTeX 2.7\miktex\bin\fc-cache.EXE: failed"
It might be due to the use of backslashes...?!
Opening MiKTeX Package Manager (mo.exe), doing a "Refresh FNDB" and a "Update Format Files" made my MiKTeX working again.
Update Wizard Log
Thank you for the report.
Unfortunately, the problem isn't reproducible. At the moment
I have not enough information to work on this problem
effectively.