All Access Pass/Slate Digital plugins are installed, but aren't in the Logic Pro Plugin Manager

On Logic Pro 10.6.3 (or later)

• If you're using Logic Pro 10.6.3 open the Plugin Manager (Logic Pro → Plugin Manager) and click Full Audio Unit Reset:
  

If you're on Logic Pro 10.6.2 or earlier you'll need to manually delete the following two files. This is also the case if Logic Pro is hanging during the plugin scan, which prevents you from accessing the Plugin Manager in Logic Pro:

Delete the AU Cache folder

• The AudioUnitCache folder can be found here:
  
  ~/Library/Caches/AudioUnitCache
  Note: All of your AU plugins will be rescanned when Logic reopens

Delete Info Helper plist file

• The InfoHelper.plist file can be found here:
  
  ~/Library/Preferences/com.apple.audio.InfoHelper.plist
  

⚠️Important⚠️: These locations are hidden by default. You will need to hold down the "Option" key on your keyboard within the Finder "Go" menu in order to access the User Library.