Freezing tracks not working with AU

I’m trying to freez some AU tracks and the clone track is empty. I used a few AU (Ruismaker and iSem) and It’s not working. Any advice? Air 1 iOS 10.2 Thanks

I create a new project and seems to be ok, sometimes not completely in sync.

Hi Ivan77,

Please have a look at the limitations of Audio Unit:

It might be possible that the AU instruments failed to load in your previous attempt.