Where are AAX Plugins Located?
This video will show you. The AAX plugin location is the same for Pro Tools, Media Composer, Pro Tools | First, and Media Composer | First (as well as other programs that can use AAX plugins).
▶Windows: C:Program FilesCommon FilesAvidAudioPlug-Ins
▶Mac: Macintosh HD/Library/Application Support/Avid/Audio/Plug-Ins
Move plugins that are causing problems to the Unused folder, or move them to the Unused folder if you don’t want them to load when you launch your program.

All AAX plugins will install to this directory by default, don’t change it! This is the ONLY path that Pro Tools or Media Composer will recognize for audio plugins.
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