Sorry about replying to your post in the Creative Suite Mac forum before seeing this one.
Wait for InDesign to hang, and then run Activity Monitor and choose Sample Process. Save and upload the results to http://pastebin.com.
Next, still in Activity Monitor, use View > Send Signal: Abort (SIGABRT) and that will cause InDesign to crash. Upload the crash report to pastebin.com as well.
Post both links here.
It might be worth just trying without Suitcase Fusion's autoactivation plugin, though. There have been reported problems with it.
This morning I tried the following, and so far, there have been no freezes:
In Photoshop, go to Preferences>Plug-ins and disable "Allow Extensions to connect to internet"
In Illustrator and InDesign, disable Suitcase Auto-Activiation.
None of them are perfect solutions, but thus far, switching between the apps has been a breeze, and none have crashed when idle. Better than nothing!
An update: Photoshop still crashed, although it took much much longer. Same for InDesign. I went into Suitcase and "uninstalled" all its CS5 plugins. Crashing stopped completely. Hope that helps.
Extensis had determined the cause of this issue and has issued patch updates for both Suitcase Fusion 3 and Fusion 4. Please review this KBA and see attached links for the latest update installers:
Contact Extensis Technical Support at (503) 274-7030 or email@example.com if you have additional questions or concerns.
Extensis Font Management Team
Please refer to this folder , move Mark II folder to the desktop and oce your problem resolved than delete it.
Location of Mark II folder :
Mac OS: [Startup Disk]/Library/Applications Support/Adobe/SING/Mark II
Note: This is in the Library folder on the root of your startup disk. There is a similar path in your user folder, but that is not the path you need to work in.
Windows 7/Vista: C:\ProgramData\Adobe\SING\Mark II\Datastore
Windows XP: C:\Documents and Settings\All Users\Application Data\Adobe\SING\Mark II