Apple Support Discussions user "John Hickman" reports:
I am having an issue where the system preferences box is not opening, so I have to force quit it and then reopen. It is not responding half the time.ASD user "Parallelogram" confirms the issue:
I am having a similar issue after upgrading to Snow Leopard. System Preferences hangs in opening about 75% of the time and must then be 'Force Quit'. It will open fine after a system restart but after a while stops responding again. It does not appear to be associated with/triggered by any other particular application or process. Have performed permission repair, no problems found.Users experiencing this issue can delete the System Preferences preference pane cache file. Navigate to username > Library > Caches and drag the 'com.apple.preferencepanes.cache' file to your Trash. Empty your Trash and restart your Mac.
Should the issue still exist, return to the username > Library > Caches folder and click on the drill down triangle next to the 'com.apple.systempreferences' file and drag the Cache.db file to the Trash. Empty the Trash and restart your Mac.
While this fix seems to work for most users, some users report that the problem continues to return. Deleting the files offers temporary repair, but does not permanently solve the issue. There is no official fix from Apple and reports are that the 10.6.2 update to Snow Leopard did not fix the problem. Users should be sure that any third-party preference panes are up-to-date and Snow Leopard compatible.