Plugin Not Showing Up in Mono Tracks

Audio Plugins
1

Hey all — I’ve been trying to get my Audio Unit plugin (built in JUCE) to appear on mono tracks in Logic Pro, and I’ve hit a wall.

I’ve followed all known best practices, including making sure the plugin supports both mono and stereo I/O, but Logic continues to ignore it for mono inserts. The plugin only shows up on stereo tracks.

Here’s what I’ve already done:

  • The plugin uses a single stereo input/output bus. I’m not creating separate mono/stereo buses.
  • isBusesLayoutSupported() explicitly returns true for both mono and stereo layouts.
  • In Projucer, my “Plugin Channel Configurations” is set to {1,1}, {2,2}.
  • AUVal confirms the plugin reports [1,1] and [2,2] channel configurations.
  • The plugin passes AUVal completely — it even lists the mono layout as valid.
  • I’ve completely cleared Logic’s AU cache:
    • Deleted ~/Library/Caches/AudioUnitCache/com.apple.audiounits.*
    • Flushed the registrar via killall -9 AudioComponentRegistrar
    • Removed and reinstalled the component from both ~/Library and /Library
    • Rebuilt from a clean Xcode build
  • Logic’s Plugin Manager shows the plugin as available and enabled.
  • I’ve tried both open -a “Logic Pro” and open -a “Logic Pro X” after resetting things — Logic rescans plugins and sees mine, but still no mono option.

The weird part:

AUVal sees and verifies 1-in / 1-out configuration just fine — so the plugin is built correctly. Logic just won’t acknowledge it in mono slots.

Has anyone solved this?

I’ve seen similar threads with no resolution. Is there something Logic caches beyond the AUVal data and Plug-in Manager? Is this a signing issue, a host bug, or something subtle in the AU wrapper?

Would love any insight — this is the last blocker before I release this plugin.

Thanks!

2

I’ve had this before and IMHO it’s Logic caching the channel info somewhere you didn’t erase. I don’t remember the location that needs to be reset, but what always worked for me is increasing the plugin version by 0.0.1 to get a true rescan of a plugin by Logic Pro. When shipping to customers one must not change channel configurations without increasing the version number. This usually goes without saying, but can be an annoyance when testing various revisions of a new plugin/release.

If that’s not an option, go deeper with the logic cache clearing. The cache(s) you deleted are not Logic’s, but the system caches. There are additional files specific to Logic Pro.

3

no dice :confused: i just tried every clear of cache I could find - downloaded it on other computers - and even updated that version number. For some reason nothing fixes this issue. I’m a first time developer, and have pretty low grasp on how to troubleshoot this error from a top down perspective.

I have plugins that have no updated audio processing - just tests with UI… and those plugins always load as stereo, dual-mono, and mono. I feel like I’ve messed something up in the audio processing chain

4

In case its of use to your situation:

$ cat ~/bin/purge_plugin_cache.sh
#!/bin/bash

sudo killall -9 AudioComponentRegistrar
rm ~/Library/Caches/AudioUnitCache/com.apple.audiounits.cache
rm ~/Library/Caches/com.apple.audiounits.cache
rm ~/Library/Preferences/com.apple.audio.InfoHelper.plist
rm ~/Library/Preferences/com.apple.logic.pro.cs
rm ~/Library/Preferences/com.apple.logic10.plist
rm ~/Library/Preferences/com.cockos.reaper.plist