Whenever you try to run sfc /scannow you get the following error:
“Windows File Protection could not initiate a scan of protected system files.
The specific error code is 0x000004dd [The operation being requested was not performed because the user has not logged on to the network. The specified service does not exist].”
Normally this is caused when you are trying to run the executable from an elevated prompt: Under Windows XP you use for example “Run As…” option.
This is by Microsoft design.
You must be logged on locally (on the console) as a member of the Administrators group. Neither elevated prompt from a non-administrative account nor RDP session can handle sfc-command properly.