InDesign freezes often and takes a long time (15-30 minutes) to begin running again with only small windows of usability. The computer isn't frozen, I can do whatever I want in any other program while InDesign is frozen, but InDesign is completely unresponsive. When InDesign is working it is not slow at all and works just fine, but it is only a matter of time before it freezes again for another extended period of time.
How can I fix it?