A client of mine was about to throw his Mac onto the South East Freeway as it was operating slower than a wet week. He was having no end of countless spinning beach balls of death while trying to run a business in law.
We uncovered the error similar to "no stores registered metascope kmdqueryscopecomputer" in his console, over and over again. It seemed this was directly related.
Although some say this is Spotlight indexing forever, even after disabling Spotlight we still experienced a painfully slow machine.
We completed the following commands in Mac's terminal.
sudo mdutil -i off /Volumes/RootPartitionName
sudo mdutil -E /Volumes/RootPartitionName
sudo mdutil -i on /Volumes/RootPartitionName
If you are attempting on "Macintosh HD" you must format like this to cater for the space in between "Macintosh" and "HD"
sudo mdutil -i off /Volumes/Macintosh\ HD
The first command disables the indexing, the 2nd clears the index database, and the third reinstates the indexing.