Q: .coremedia.videomediaconverter

Hi imeloun,

What are you attempting to do in iTunes when the software becomes unresponsive?  Are you connecting to the iTunes Store, or playing a video file?  Your profile doesn't indicate what version of iTunes you are using.  My first suggestion would be to make sure your iTunes software is up to date.  If you are trying to open a specific file, try a different file to see if the issue persists.  You can also start your computer in Safe Mode or create another user to test the application.  I'll include some troubleshooting resources below for you:

Mac OS X: How to troubleshoot a software issue

Resolve issues between iTunes and third-party security software

Take care,