I have had this semi-confirmed during a chat with Apple Tech Support but the bug does not seem to affect everyone on any given OS version so I'll call this a possible cause/bug rather than a confirmed one.
Alert: This 'test' involves the re-indexing of your drives in Spotlight and as such could take several hours to complete depending on how many drives you have and how much data you have stored on them.
If after updating to 9.1.6 you are getting the spinning beach ball and/or a Kernel Panic/Crash when you either start Logic or when you open a project then...
Go to System Preferences/Spotlight/Privacy Tab
Add every HD you have connected to your computer.. both internal and external with the exception of your System (The drive your OS is installed on) to the exclusion list to the Privacy tab and then restart the computer.
Start Logic and see if that stops the issue you are having.
If it does... delete each HD you added to the Spotlight Privacy List, one and a time.. wait for Spotlight to finish re-indexing that drive and then start Logic again and check all is ok.
(If it doesn't help.. add back all your drives, one at a time and let Spotlight re-index each one.. Warning.. This could take some time so be prepared to wait!!)
Carry on doing this until you get an Issue with Logic once more and add that particular HD to the Privacy list once more and carry on testing out the rest of your HDs until you have re-indexed and tested them all without further issue in Logic.
This method worked for a client of mine who was having this issue with 10.6.8 and 9.1.6 and it also worked for a Lion 10.7.2 Mac that was having the same issue. In both cases one drive (In both cases an External USB2 HD formatted correctly as Extended Journaled) was found to be the cause of the issue. For whatever reason a re-format of the offending drive, did not fix the issue for either of them.
There is no reason that is fully understood at this time.. why these particular drives started to have an issue with Spotlight. They were different drives from different manufacturers.
If this works.. or doesn't work for you.. please leave appropriate feedback here..
Thanks!
