After Effects Error Asked To Create Unknown Property Of Type Fix Upd Jun 2026

This comprehensive troubleshooting guide breaks down why this error occurs and provides concrete, step-by-step methods to fix it. What Causes the "Unknown Property of Type" Error?

Press Ctrl+Shift+C (Windows) or Cmd+Shift+C (Mac) to pre-compose it.

Opening a project that uses effects you don't have installed can trigger "Unexpected data type" or property creation errors. Step-by-Step Fixes 1. Identify and Remove Problematic Scripts Opening a project that uses effects you don't

You created a Motion Graphics Template (MOGRT) or used the Essential Graphics panel. Sometimes, creating a "Master Property" and then deleting the underlying source (like a shape layer) causes this "unknown property" error because AE is still trying to create the Master Property link.

: A dedicated "Safe Open" that strips all non-native effects to allow project recovery without crashing. If you'd like to try a specific fix, let me know: Sometimes, creating a "Master Property" and then deleting

Inspect expressions and JSON/Essential Graphics

Look for a .jsx or .aefx file that needs to be copied into the ScriptUI Panels folder mentioned above. 5. Clear Cache and Reset Preferences Opening a project that uses effects you don't

The following plugins have historically triggered "unknown property of type 'fix'":

. If the project opens cleanly, add your scripts back into the folder one by one to find the specific script causing the crash. 2. Update Legacy Expressions

Many advanced presets and templates use custom "Pseudo Effects" (hidden control groups). If a preset names a custom controller using an internal command string (like the word "Layer"), it creates a naming conflict that blocks After Effects from generating shapes or null layers.

Often, this re-links the expressions properly and resolves the error. 3. Identify and Remove Third-Party Scripts/Plugins