AUv3 "Failed to find component with type..." frequent issues

Question

Created 7h

Replies 3

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This post is from the WWDC26 Audio Q&A.

When the host app of a host/AUv3 extension pair tries to find the audio extension it fails. The system should have scanned the bundle for the extension, but this appears to fail. This basically happens in SimplePlayEngine.initComponent.

I've seen this intermittent problem for years. There are many sometimes-effective workarounds that I've gathered and used, but the problem still exists. It is not a problem of validation -- the same AU can validate in some run cycles and then not be found via the host app in others.

I've got a Feedback Assistant ticket for the latest iteration of the problem (FB22860885), which has affected beta testers. Usually I only see this when developing with Xcode myself. So even though the testers' app lives in ~/Applications it is still failing for some of them.

Answered by Frameworks Engineer in 890491022

We are aware of this issue. Unfortunately we cannot tell you any details on the status of it. It's a complex interplay of the Audio Unit framework the PluginKit framework and NSExtension which can lead to updates about extensions being added or removed to not being delivered.

Answer 1

Frameworks Engineer OP

Apple

6h

Accepted Answer

We are aware of this issue. Unfortunately we cannot tell you any details on the status of it. It's a complex interplay of the Audio Unit framework the PluginKit framework and NSExtension which can lead to updates about extensions being added or removed to not being delivered.

Answer 2

mad poet navarth OP

6h

I have not seen this on iPad. I'm wondering if this is a mac-specific issue, as I'm ready to do an iPad beta test of this.

Answer 3

Systems Engineer OP

Apple

6h

Hi. Thank you for the feedback! Placing the container app in ~/Applications shouldn't be necessary. The extensions vended by an app are registered on the first launch of that app (on macOS). Once registered, these extensions should be discoverable by all AU host apps. Ocassionally, multiple apps (or different versions of the same app) register different versions of the AU with the same type, subtype, manufacturer. In these cases, the highest version number will win.

You can run "auval -al" to list all available Audio Units on the system and their location. "pluginkit -mv" will list all extensions (of all types, not just Audio Unit Extensions) and their location.

Does the AU pass auval ? If you are able to capture this problem in a sample app along with clear instructions on how to reproduce it and attach that to the Feedback Assistant, that would be tremendously helpful.

I hope that helps. Best Regards!