Logic & GarageBand

1. Make sure you've downloaded the correct installer from the Korneff Audio site, which would be a the .pkg file, as well as updated to the most recent version of iLOK License Manager.
You can get your iLOK License Manager here.

2. Confirm the plug-in is properly installed to your system's plug-in folder.
Open Finder, click Go on the menu bar at the top of your screen, then Go to Folder and enter "/Library/Audio/Plug-Ins/Components" into the Go to Folder field, then click Go.

3. If the plug-in is not appearing in Logic or GarageBand, perform a rescan. To do so, go through the following steps:
Open Finder, click Go on the menu bar at the top of your screen. Hold down the Option key (⌥) and Library should appear in the drop down menu. Click on that to enter your User Library. Open the Caches folder and then open the AudioUnitCache folder. Inside there, delete any of the following files:
» com.apple.audiounits.cache
» com.apple.audiounits.sandboxed.cache
This will force Logic or GarageBand to rescan all of your AU plug-ins when you restart (it may take a few minutes). 

Note: GarageBand users may also need to go to the Preferences folder in the User Library and delete the following file:
» com.apple.audio.InfoHelper.plist

4. If the plug-in fails validation in Logic:
Open the Plug-In Manager from within the Preferences menu and type in "Korneff Audio" in the search box. Then, select the plug-ins that fail validation by holding the Command key (⌘) and clicking them. Once the plug-ins are selected, click the Reset & Rescan Selection button at the bottom of the Plug-In Manager window and wait for the validation to complete. This could take several minutes.

Once validation is completed, open the plug-in to verify it is working properly on your system.