Are you running suitcase? I believe there was an issue with auto-activation and delays that was causing this, and that it was fixed with an update to suitcase.
Just to be perfectly clear, have you tried trashing your preferences
Trash, Replace, Reset, or Restore the application Preferences: http://forums.adobe.com/thread/526990
After that well, when InDesign hangs, there are two chunks of data we can look at to see why it hangs. Please save both of them and upload them to http://pastebin.com/, and post a link here. Please don't post the data here, it is too large for this forum and makes the forum un-navigable.
Obtain both by running Activity Monitor and selecting InDesign.
1. Sample Process. Save to file.
2. View > Send Signal: Abort (SIGABRT). You'll get a crash report. Save to a file.
Upload both and post links here.
Thank you for your quick responses. I am running Suitcase Fusion 3 and have not updated it in quite some time. I updated Suitcase and everything is working fine now.
Just to be clear to anyone else reading this forum with the same issue, simply turning off the auto-activation feature (and even deleting the auto-activation plugins in the InDesign application folder) did NOT work. You must apply the update to Suitcase.
I really can't thank you enough Peter for pointing this out.
John, I did try trashing my preferences. I failed to mention that in the steps that I took above, but that you for that suggestion. The outdated Suitcase was definitely the issue.