Since my latest Mac OS upgrade Spotlight is acting up on a regular basis, indexing the hard drive over and over, rendering my Mac nearly unusable. Only workaround I could find on the web was turning spotlight off. Works as a quick'n'dirty fix if I don't have time for a prolonged coffee break.

Bash: Switch Off Spotlight

# Reminder: After turning Spotlight back on, 
# it will start re-indexing, 
# which may take quite some time and 
# thus might best be done overnight.

# Switch off Mac spotlight

  sudo mdutil -a -i off

# Turn Spotlight back on.

  sudo mdutil -a -i on

# This comes without warranty. 


# another potential solution/temporary remedy:
# http://guidovanoorschot.nl/how-to-fix-spotlight-when-it-keeps-indexing-n-mac-os-x-lion/

  sudo rm -rf /.Spotlight-V100/*

  sudo mdutil -i on -E /