From MacFixIt
Unable to run Disk Utility after update Several users have reported that they are unable to properly run Disk Utility after applying the iTunes 6.0.2 update, receiving the error message:
"Disk Utility lost connection with Disk Management Tool and cannot continue."
part-way through the repair process.
The problem generally affects users running Mac OS X 10.3.9.
MacFixIt reader Philip Wheelock writes:
"I installed iTunes 6.0.2 via Software Update; restarted and found I could not repair disk permissions with Disk Utility, even starting from system installer disk. Disk Utility stalls approximately 1/3 of the way through and displays this error message: 'Disk Utility has lost its connection with the Disk Management Tool and cannot continue. Please quit and relaunch Disk Utility.' Never seen this before."
There are two potential workarounds for this issue:
Delete the "Chess" application and its associated .plist file (com.apple.Chess.plist, located in ~/Library/Preferences -- the Library folder inside your user directory) and attempt to re-run Disk Utility
Delete iTunes 6.0.2 and its associated .plist file (com.apple.iTunes.plist, locaed in ~/Library/Preferences). Re-install iTunes 6.0.1 (from a backup, if available) and attempt to run Disk Utility again.
If you are still having issues, note that you can still startup from a different volume (or the Mac OS X installation disc) and repair permissions successfully on your normal startup volume.
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Solution 2;
Disk Utility crash
The iTunes 6.0.2 update of 1/12/06 screwed up at least two files:
folder: your disk -> Library -> Receipts
files: iTunes.pkg, iTunes4.pkg
Other files from their-party plug-ins to iTunes may also be a problem.
Solution:
1) Archive these files so that Disk Utility can not see them anymore**. My solution was to put them into a StuffIt archive.
2) Delete these files
3) Run Disk Utility, Repair Permissions
4) Run Disk Utility, Repair Permissions again"