I have experienced the exact same issue since few days as well (AFAIR about 2 days ago), and am trying to find a solution.
This is what my OSX Console log (Apps > Utilities > Console) looks like, just after selecting a program / document in spotlight results:
04/03/2015 14:29:27,288 WindowServer: disable_update_timeout: UI updates were forcibly disabled by application "Spotlight" for over 1.00 seconds. Server has re-enabled them.
04/03/2015 14:29:41,289 WindowServer: disable_update_likely_unbalanced: UI updates still disabled by application "Spotlight" after 15.00 seconds (server forcibly re-enabled them after 1.00 seconds). Likely an unbalanced disableUpdate call.
04/03/2015 14:30:11,296 Spotlight: Hang timer fired; exiting
04/03/2015 14:30:11,299 spindump: Got xpc error message in libspindump client connection: Connection invalid
04/03/2015 14:30:13,675 Spotlight: applications query - started
04/03/2015 14:30:13,808 Spotlight: applications query - finished in 0.13 seconds
System: OS X 10.10.2 Yosemite
Issues seem to start about right after having installed Duet Display and rebooted.
However, there's one thing that can be done to isolate spotlight issues and that's to run the command
sudo /usr/bin/mddiagnose and either dig into the collected error logs or forward them to your support chain (Apple Support if you don't have a support team/IT department).
- Open terminal.app (by navigating to /Applications/Utilities in Finder if needed)
- Run the command
- Check to see if spotlight is still hung: repeat the
mddiagnose each time it hangs to get a sense of how often this happens
- repeat as needed
That tool will package all the system logs surrounding the event as well as check for crashes and specific error messages that might point to the cause of spotlight hanging.