Logic Pro X Always rescans audio units on startup


New Member

Logic is constantly re-scanning audio units on startup. How can I stop this.

Mac OS sierra 10.12.6 (16G29)

Logic v.10.4.0




New Member
I’d love to hear an answer to this as well. Logic scans all 132 of my 3rd party AUs every time I start. It’s a tiny bit annoying


New Member
I got an answer to this from the KVR forums. It worked! I did both things suggested. I’ll just paste the info here for future reference:

I've heard of this behavior before. It was usually either a permissions issue related to the AudioUnits cache or some old Waves waveshells not scanning correctly, so Logic gets stuck in a loop rescannning them on every launch. I would check the caches folder:


There should be a decently sized com.apple.audiounits.cache file in there. If there isn't or it's 0kb, then maybe something is preventing it from being written. Try deleting the whole AudioUnitCache folder and let Logic recreate it. Maybe that will fix it. Also check ~/Library/Audio/Plug-Ins/Components to see if there are multiple waveshells present, which can sometimes clash with each other. Over the years I've had to run the Waves AU reg utility to fix issues with their plugins. It used to be found in the Applications/Waves/Waveshells folder.

Tosh Nanda

New Member
Hello Guys,
Finally I have found a permanent solution to this issue.
1.Copy All files from Macintosh HD /Library/Audio/Plug-Ins/Components/
2.Paste to Macintosh HD/Users/your user name/Library/Audio/Plug-Ins/Components/
3.Click on Replace All

Next time when you start logic it will scan all audio units only once and the scan wont reoccur in every subsequent startup.

Best Wishes :)


And now you have 2 copies of each plugin - one in /Library/Audio/Plug-ins/Components and one in ~/Library/Audio/Plug-Ins/Components