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Posted on February 14, 2012 by Joe Stachowiak There have been 6 comment(s)

Please note that this tutorial was written for Logic Pro 9 and although the basic principles are likely to remain the same for future updates, some of the screenshots may not exactly match up with what you see in future versions.

To rescan for Audio Units in Logic:

1. With Logic open, select Logic Pro → Preferences → Audio Units Manager… from the menu bar.

Logic Audio Units Manager Menu Item

Logic Audio Units Manager Menu Item

2. Click the 'Reset & Rescan Selection' button, followed by 'Done' once the scan has completed and given you a report.

Logic AU Manager

Logic AU Manager

NOTE: This process should be followed after installing plug-ins/updaters, or moving AU components in the Finder.

Further information on the AU manager & manual plug-in activation:

Logic uses the Apple AU Validation Tool to ensure that only plug-ins that fully comply with the Audio Units specification are used with Logic Pro. This process minimises problems that may occur when using third-party Audio Units. You can choose to manually activate Audio Units that fail the validation test by selecting the checkboxes in the Logic column. However, be warned that these plug-ins can cause problems (in some cases even loss of data), so it is not recommended!

If you decide not to heed the warnings and activate plug-ins with failed validations, and find that it prevents Logic from opening:

1. Hold Control-Shift when opening Logic.

This opens Logic Pro in Audio Units safe mode – only plug-ins that pass the validation test will be available in this mode.

This post was posted in Blog entries, Computer Music, How To Guides and was tagged with audio units, logic, logic 9, logic pro


  • If you have 3rd party AUs that aren't showing up for some reason, switch from 64 to 32bit (or vice versa) and reopen Logic. This makes Logic rescan your AUs. Close Logic and switch back to your preferred bit rate. Worked for me!

    Posted on June 19, 2012 at 8:27 pm

  • Nice one, thanks for the tip :)

    Posted on June 20, 2012 at 9:32 am

  • have exact same problem!!!

    Posted on July 31, 2012 at 11:10 am

  • Hi Richie, have you fixed the problem?

    Posted on July 31, 2012 at 11:14 am

  • AZ says:

    How do you do a rescan for all audio units? Say, if you've just added one but don't want to restart Logic...

    Posted on August 19, 2012 at 4:57 am

  • Hi, thanks for the question. As far as I can tell, you have to restart Logic for plug-ins to show up in the audio units manager if you install them whilst Logic is running - I've certainly not managed to find a way around this if there is one. Sorry about that

    Posted on August 20, 2012 at 10:41 am