The bug usually happens when Adobe After Effects tries to read a third-party script, outdated expression template, or an unsupported pseudo-effect that your current software version cannot recognize . This error can interrupt your workflow, cause random software crashes, or block you from opening a .aep project file entirely. What Causes the "Unknown Property of Type" Error?
: C:\Program Files\Adobe\Adobe After Effects (version)\Support Files\Scripts\ScriptUI Panels
Click "Yes" when asked if you want to delete the preferences file. Step 5: The "New Project" Import Trick The bug usually happens when Adobe After Effects
If you don't need the effect, delete the missing effect layer and resave the project. Step 3: Purge Memory and Disk Cache
: Go to File > Scripts > Update Legacy Expressions.jsx . This can often resolve issues where expressions are trying to call properties that have changed in newer software versions. Identify and Reinstall Missing Plugins/Presets This can often resolve issues where expressions are
Open the underlying XML or control script associated with the custom effect.
This is the most common cause. Complex shapes with multiple animators, paths, and styles can confuse expressions. Complex shapes with multiple animators
A prompt will ask if you want to delete your preferences file; click . Leverage Safe Mode Troubleshooting
To fix the , you must address outdated expressions, missing third-party plugins, broken ScriptUI panels, or script syntax mismatches. This error typically occurs when a project file, preset, or script tells Adobe After Effects to look for a core property, custom parameter, or "pseudo-effect" that does not exist in your current version of the software.
: This error frequently points to a missing third-party effect (like Magic Bullet Looks or Red Giant ). Make sure all the plugins used in your project or preset are actually installed.