Troubleshooting Logic Pro Plugin GUIs on Sonoma

Sometimes, technical support involves more than just fixing a specific issue; it requires a structured approach to elimination and a clear path forward. This recent session with a client is a good example of how I approach diagnosing elusive plugin problems within a complex system like Logic Pro running on macOS.

I connected with the client remotely through Audio Support to help him solve a persistent visual glitch.

The Client’s Challenge

The client is a producer using Logic Pro on a Mac running an older version of macOS Sonoma. He relies on key third-party plugins, specifically Sonnox Oxford Inflator and Rift by Minimal Audio, for his work.

The core problem was frustrating: the Graphical User Interfaces (GUIs) for these plugins would randomly display as solid black squares instead of their normal controls. This made the plugins unusable until he restarted Logic Pro. Crucially, the issue would return unpredictably, severely disrupting his workflow. I had actually seen this behaviour myself in a previous brief check, so I knew the problem was genuine and specific.

Diagnosis

My first step was to check the common causes for plugin display issues in Logic Pro. The most frequent culprit is the “Editor” vs. “Controls” toggle within Logic’s plugin window, but I quickly confirmed this was not the case. This meant the issue was deeper.

I methodically checked all the standard locations where plugin conflicts can occur:

• I inspected his Component (.component) folders in both the main System Library and his User Library to look for any duplicate or corrupted files.
• I examined the integrity of the Audio Units plugin cache.
• I confirmed that the licenses for both the Sonnox and Minimal Audio plugins were valid and loading correctly.

Nothing stood out as an obvious cause.

Next, I noted his operating system. He was running an earlier version of macOS Sonoma. While Sonoma has seen some reported issues with Audio Units (AU) plugins, this specific black GUI problem wasn’t something I had encountered or found widely reported online. My research during the session also only pointed back to the common “Editor/Controls” fix, which we had already ruled out.

Reflection