THE ANSWER — NO SOLUTION
It seems that this is a (hardware?) bug with the Intel iMacs and Mac Minis, as I discovered in this thread on Apple Support (which admittedly wasn't easy to find with that title, but it fits my problem to a tee).
Going to have to wait for Apple to come up with a fix. Ire rising…
Essentially, I had numerous system crashes caused (it seems) by iTunes downloading media: the system would hang irrecoverably. I couldn't even log in over SSH, though CoreGraphics continued to let me move windows around.
For more information on the background to this problem, please consult iTunes causes the entire system to crash when downloading some media OS X
Becoming frustrated, I decided to perform a clean install of OS X. After wiping and installing OS X 10.6 (as case-sensitive and journaled, which I had used in past but had not used on my last install) and the Combo 10.6.5 (and all other relevant) updates, I began restoring my machine's data from Time Machine.
I restored preferences, documents and my Aperture library in separate restore batches. But when it came time to restore my iTunes Music Library (i.e., ~/Music/*) the system crashed part-way through writing files in a very similar manner: the cursor would move on the screen but the system was otherwise totally unresponsive, including SSH.
I can only surmise that the culprit lies somewhere in my 385 GB of media, which represents about 35 000 individual files. It's likely a file which is corrupted:
- The file name uses characters that the system, for whatever reason, can't handle. I have a large number of file names that contain both Arabic or Hebrew (which are both right-to-left languages) and English. I also have a number of file names in Cyrillic, French and other languages. The Terminal doesn't seem to have a problem displaying them and I've never had trouble copying them either in the shell or in the Finder. Seems worth mentioning, anyway.
- I may have somehow added a file which is corrupted or which violates Apple's allowable file naming scheme (say, containing null characters).
- Some sort of permissions error in a subfolder. I repair permissions regularly, but as we know, it may not modify permissions of files which can "function with different permissions".
I now have two problems: (1) how do I determine if this is a file name or file-related problem; and (2) how do I figure out which file is the culprit? system.log and Console.app's "Diagnostic and Usage Messages" have no useful output. Furthermore, restoring the files manually from the Time Machine volume using
cp -Rnv time_machine ~/Music/ has worked and not caused an error.
I should add that I have preserved my iTunes Library (not just the files but the actual .xml file) since 2005, restoring from backups on OS and hardware upgrades. I would be surprised if I had not introduced corruption along the way from all that manipulation, chiefly filesystem changes (starting at Mac OS 9, migrating to and from case-sensitive volumes) over the years...
I'd appreciate any advice. The AKB hasn't been particularly helpful.
EDIT (QTKitServer): An AKB article on QTKitServer being a CPU hog got me thinking, especially after I saw it in Spin Control: perhaps that's the process that's bugging out at some point; I've just disabled Finder's show icon previews. I guess we'll see!