Sometimes you find an InDesign file that seems to cause problems. It could crash unexpectedly. It may be acting bizarre. Or it may just have something like a “phantom font” or a spot color that appears even though it’s really not there.
A good troubleshooting technique is to export an IDML file (in InDesign CS4, CS5 or CS5.5) or an INX file (in InDesign CS2 or CS3). These are XML files that contain all the information in the file (but not the graphics). Saving them is sort of like giving your file a deep cleaning.
In InDesign CS4, 5 or 5.5, choose File > Export. In the Format menu select InDesign Markup (IDML). Save the file.

In InDesign CS2 or CS4, choose File > Export. In the Format menu select InDesign [Version] Interchange (INX). Save the file. (The version will be the number of the previous version.)
Then re-open the file in InDesign, and see if it fixes the problem.
These formats were designed to save backward to the previous version of InDesign. But sometimes they can also get rid of hidden corruption.

Remember that these files don’t contain the graphics so to reopen them you still have to have access to the linked graphics referenced in the file.