Ron Gomes: We're glad you like that. Unfortunately, we're tracking a bug in OS X itself which may force us to require that restart as we have previously - we'll have to see.

Marc Barnes: I'm not sure what you're seeing - hijacking will continue if you only turn off the Record button, but the recording itself will be stopped. That's to be expected, and how it's always worked. Hijacking from a source means its audio is coming into Audio Hijack Pro, while Recording means that audio is being saved - recording requires hijacking, but hijacking can be done without recording (to add effects to audio, for instance).

As far as iTunes goes, that sounds like an iTunes issues. If you double-click and the file opens in iTunes, that's a setting on your specific machine (you can configure what application handles file types by selecting "Get Info" on a file of a particular type). Deleting the file in iTunes is definitely an iTunes issue.

If you're having additional issues, you'll want to get in touch via support.