Originally Posted by paulsalter
when i check in activity monitor for iTunes it says that it is not sandboxed (unlike Safari which it says is)
I am guessing about the sandboxing because from version 10.6.1 to 10.6.3 iTunes fails to respond to OSA queries, and it's been widely anticipated for some time that iTunes would have OSA access turned off. Apart from a bug on Apple's part that somehow managed to entirely shut down OSA for iTunes, I don't know what else might have caused the sudden blackout.
I see that the sandboxing status shows 'No' in Activity Monitor (thanks for pointing that out, I didn't know that was available). Another possibility is that Apple simply shut down OSA for iTunes.
It could also be that calibre, as an app not distributed by the app store, has been sandboxed, thus shutting down OSA communications. However, iTunes version 10.6.1 still works with the latest calibre release (0.8.56).