After Effects Expression Error (Expression Disabled / Object of Type Found)
Quick answer
Errors like 'Object of type ... found where a Number, Array, or Property is needed' come from old expressions in the new JavaScript engine. Test with Legacy ExtendScript, then update the code.
Most likely fix: Confirm with the Legacy engine
How to fix it
Try these in order — the most common fix is first.
1. Confirm with the Legacy engine
- File > Project Settings > Expressions
- Set Expressions Engine to Legacy ExtendScript
- If errors vanish, the code needs updating
Did this fix it?2. Update the expressions
- Replace 'this' with 'thisLayer' where used for the layer
- Do not end the expression with a function declaration
- Check Adobe's 'Syntax differences between expression engines' page
Did this fix it?3. Run the upgrade script
- Switch back to JavaScript engine
- File > Scripts > Upgrade Legacy Expressions.jsx
- Back up first; it does not fix every difference
Did this fix it?
Symptoms
Yellow warning bar, expression disabled, or 'Object of type found' after opening an older project or template.
Why it happens
- Expression ends with a function declaration
- 'this' used as shorthand for thisLayer
- Syntax differences between Legacy ExtendScript and JavaScript engines
This guide also covers
- after effects expression error
- after effects expression disabled
- object of type found where a number array or property is needed
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