The path to the repository location changed automatically.
After working a while with Spotlight, it loose the path to the repository location and change it to the default location.
User can change the path back to the location he/she wanted, but after restart the changes are lost and Spotlight uses the default location again.
Only new installation of Spotlight fix the error.
There's enough space on the repository location.
Uninstall Spotlight and run the QCClean utility.
Install the newest version of Spotlight (4.5).
To get the QCClean utility contact Quest Support at firstname.lastname@example.org.