I recently upgraded DP to 4.1.2 and haven't been able to get it to recognize any of the Audio Units. I have installed Crystal the free synth and pro-53 by live instruments into the /Library/Audio/Plug-Ins/Components/ folder in os x.2.8 and none are available to add to an instrument track. I have tried trashing every Digital performer preference file I could find. I read that it might take a few minutes to load DP after installing a new component and that it won't load them if they are damaged, but DP doesn't even attempt to load the .component files among all of its own plugins.
If anybody has any ideas it would be much appreciated. Like where does DP keep info on components? Has anybody had and resolved this issue?