Severe UI Lag Caused by Audio Plug-in Resolution Failures

I’ve isolated the cause of the severe UI / timeline / menu lag I’ve been experiencing in recent Premiere Pro Beta builds.

Summary of findings:

• Premiere Pro Beta becomes effectively unusable when audio plug-ins are enabled

• With all audio plug-ins disabled, Premiere functions normally (timeline interaction, menus, selection, Reveal in Project all return to normal responsiveness)

• Re-enabling audio plug-ins immediately causes extreme sluggishness across the entire UI, even when audio plug-ins are not actively used on clips

Additional evidence:
On startup / project open, Premiere reports multiple missing audio filters, including explicitly:

• iZotope Alloy 2

• Numerous additional audio filter IDs (numeric / hex identifiers)

Example message:

Audio Filter missing: iZotope Alloy 2
Audio Filter missing: [multiple internal plug-in IDs]

These missing or legacy audio plug-ins appear to cause the audio engine to stall, which in turn blocks the UI/event loop. This results in:

• Timeline selection delays

• Right-click/context menu lag

• Menu selection delays

• “Reveal in Project” taking 15–30+ seconds

• General editing being too slow to be usable

Key point:
This is not project corruption, GPU, OS, or media related. The behavior is fully controlled by whether audio plug-ins are enabled or disabled.

Workaround:

• Disable all audio plug-ins → Premiere becomes usable

• Audio work must be deferred or handled externally

This appears to be a regression or failure in how the Beta handles missing / deprecated audio plug-ins and their interaction with the UI thread.

System Information:

• Mac model: Mac Pro (2023)

• Chip: Apple M2 Ultra

• Memory: 192 GB

• Startup disk: Macintosh HD

• macOS: 14.6.1 (23G93)

• PCIe: 7 PCI Card Slots/ 2 used for OWE Accelsior drives