I recently ran into an error on Mac OS 10.9 about Spotlight being disabled:
mdutil[81198:507] Metadata.framework [Error]: mdsCopyStorePaths failed: (268435459) (ipc/send) invalid destination port Spotlight server is disabled.
I had turned off Spotlight indexing, so I thought that is what it meant by Spotlight being disabled. That wasn’t the case.
Fortunately fixing this error is simple, run this as root:
launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist
The I turned Spotlight indexing off again with mdutil -a -i off.