WARNING: Don't use any disk-cleaner apps, it deletes the AudioUnitCache folder

Finally found out why Logic kept scanning audio units each time on start up: It was a disk cleaner app.

 

It seems like disk cleaner apps try to completely clear out the cache folder when deleting "junk," which includes the AudioUnitCache folder. If Logic has to keep scanning plug-ins on startup, its probably because that folder keeps being deleted. I found this out about a year after discovering the problem.

 

If you still want to use one of those apps, add a lock to that folder and the file within. It'll prevent it from being deleted automatically.

 

Really hope someone else find this useful here.

All those apps that clean your Mac or make it faster and the like are more harmful than beneficial.

Stay away from them, regardless of what they promise.

I have never used a disk cleaner app (or any other Mac "optimization" utility) in my 22 years of owning a Mac and being a consultant to professional music producers.

I agree with avoiding any third party software that does its own thing with your system and files. My first Mac was the Apple IIci which I bought in 1989 and have had a string of them since, 31 years of amateur, semi-professional and professional use now. I like David have never used a cleaner until I got an Adware bug from stupidly clicking an update for Adobe Flash in a moment of distraction. Malwarebytes sorted it out. But CleanMyMac and Combo Cleaner wanted to access more than I was prepared to let them.

I do Macs for a living, there is no reason to use and no benefit from any disk cleaner/system optimizer things. Quite often they are malware and the Mac OS doesn't need any of it.

But there may be an occasional benefit from manually backing up the cache file. On a major osx upgrade or even transfer to a new computer via time machine, the cache doesn't get backed up or restored, but can be manually restored. this really isn't a big problem unless you have very large amount of plugins.

But there may be an occasional benefit from manually backing up the cache file.

But this requires you to know *exactly* what you're doing. Plugin versions might be slightly different (they will if you're migrating from an old to a new computer), paths might be different, etc.

Lots of potential of provoking weird system behaviour later when you least expect it. Not recommended.