This message will appear in any/all of the following situations:

1) There are any values in the registry under

2) On Windows NT-based systems, if the "PendingFileRenameOperations"
value is set under

"HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Session Manager"

3) On Windows 9x-based systems, if there are any files listed in the
[rename] section of the wininit.ini file.

A complete description of this is available at the following page:

Begin by checking if there are any values under the RunOnce key, then check PendingFileRenameOperations. It's not a good idea to just delete these values out of hand; check what they're running or renaming first. A reboot should clean out the PendingFileRenameOperations. Some viruses may put themselves under RunOnce so a full virus scan of the system may be in order as well.