I have exhausted standard debugging approaches and need guidance on Final Cut Pro's AU plugin loading behavior.
PLUGIN OVERVIEW
My plugin is an AUv2 audio plugin built with JUCE 8. The plugin loads and functions correctly in:
- Pro Tools (AAX)
- Media Composer (AAX)
- Reaper (AU + VST3)
- Logic Pro (AU)
- GarageBand (AU)
- Audacity (AU)
- DaVinci Resolve / Fairlight (AU)
- Harrison Mixbus (AU)
- Ableton Live (AU)
- Cubase (VST3)
- Nuendo (VST3)
It does NOT load in Final Cut Pro (tested on 10.8.x, macOS 14.6 and 15.2).
DIAGNOSTICS COMPLETED
- auval passes cleanly:
auval -v aufx Hwhy Manu → AU VALIDATION SUCCEEDED
- Plugin is notarized and stapled:
xcrun stapler validate → The validate action worked spctl --assess --type exec → Note: returns 'not an app' which we understand is expected for .component bundles.
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Hardened Runtime is enabled on the bundle.
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We identified that our Info.plist contained a 'resourceUsage' dictionary in the AudioComponents entry. We found via system logs that this was setting au_componentFlags = 2 (kAudioComponentFlag_SandboxSafe), causing FCP to attempt loading the plugin in-process inside its sandbox, where our UDP networking is denied. We removed the resourceUsage dict, confirmed au_componentFlags = 0 in the CAReportingClient log, and FCP now loads the plugin out-of-process via AUHostingServiceXPC_arrow.
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Despite au_componentFlags = 0 and out-of-process loading confirmed, the plugin still does not appear in FCP's effects browser.
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We also identified and fixed a channel layout issue — our isBusesLayoutSupported was not returning true for 5-channel layouts (which FCP uses internally). This is now fixed.
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AU cache has been fully cleared:
- ~/Library/Caches/com.apple.audio.AudioComponentRegistrar
- /Library/Caches/com.apple.audio.AudioComponentRegistrar
- coreaudiod and AudioComponentRegistrar killed to force rescan
- auval -a run to force re-registration