Edited: As things seem to be on a downward spiral now.... My setup is a 27" C2D iMac, 4GB RAM, running SL, all latest updates. iTunes is latest version with the library hosted on an external Drobo connected via FW800. I have no iPods plugged in just now and have disabled automatic sync with my ATV so I know there shouldn't be any tasks running within iTunes itself. This morning I get a message about a corrupt iTunes library. I restored the file from a backup and after a long time referencing the corresponding .xml file, iTunes loaded up. 95% of the library was fine, but for some reason, it had lost some files, leaving me with exclamation marks scattered around the place. If I manually locate the file, that solves the problem, so while its a pain, I can sort it out, or I guess the new equivalent of consolidate library should clear it up. Anyway, for the last few hours, iTunes is very slow. Rest of the machine is fine and its not hogging resources according to activity monitor, but its clearly doing something which is making it appear to be un-responding. When I switch to it, it takes a while to appear, then the spinning beach ball, then maybe 30 seconds to a minute later, it becomes active for a short time before becoming unresponsive again. Any ideas about what could be causing this? Thanks.