"asked to create unknown property of type" in Adobe After Effects typically occurs when the software encounters a script, preset, or template that references a property or "pseudo-effect" it doesn't recognize or can't access. Common Causes & Fixes Missing Plugins or Presets
: This often happens when you try to apply a preset that requires a specific third-party plugin you haven't installed (e.g., Red Giant Universe or Boris FX).
: Ensure all required plugins are installed and updated. If the preset came with a tutorial or documentation, double-check for "pseudo-effects" you were supposed to install first. Outdated Expressions
: Templates created in older versions of AE may use code that is no longer supported by the modern JavaScript engine. File > Scripts > Update Legacy Expressions.jsx
to let After Effects attempt to update the code automatically. Corrupt Preference Files
: Corrupted background settings can prevent AE from loading properties correctly. : Reset preferences by holding Ctrl+Alt+Shift (Windows) or Cmd+Opt+Shift (Mac) while launching After Effects. Extension Boot Issues
: If you use extensions like Mt. Mograph Motion v4, the error may stem from a failed initial boot of that panel. : Close the extension panel (right-click the title and hit Close Panel ) and then reopen it via Window > Extensions Script UI Conflicts
: A specific script running in the background may be the "troublemaker". : Temporarily remove files from the Scripts/ScriptUI Panels
folder, then add them back one by one to identify the one causing the error. General Troubleshooting Steps Purge Cache Edit > Purge > All Memory & Disk Cache to clear potentially corrupt temporary files. Import into New Project : Create a brand new project file and then go to File > Import > File
to bring your old project into it. This can sometimes bypass project-level corruption. Change Expression Engine File > Project Settings > Expressions , try switching the "Expressions Engine" to Legacy ExtendScript Error: asked to created unknown property of type "x" (1d16)
"asked to create unknown property of type" error in After Effects typically occurs when the software tries to access a feature, effect, or script parameter that it doesn't recognize. This usually points to a missing plugin, an outdated expression, or a conflicting script. Common Fixes Install Missing Plugins:
This error often triggers when you open a project or apply a preset that requires a third-party plugin you don't have installed (e.g., Red Giant Universe Boris FX Continuum Update Legacy Expressions:
If the project uses expressions from older versions of After Effects, the engine may struggle to read them. Go to File > Scripts > Update Legacy Expressions.jsx to automatically update them to the modern engine. Remove Conflicting Scripts:
A buggy script in your "ScriptUI Panels" folder can cause this on startup. "asked to create unknown property of type" in
C:\Program Files\Adobe\Adobe After Effects [Version]\Support Files\Scripts\ScriptUI Panels
/Applications/Adobe After Effects [Version]/Scripts/ScriptUI Panels
Try moving scripts out of this folder one by one to identify the "troublemaker". Change the Expression Engine:
In some cases, switching the engine back to the older version helps. Go to File > Project Settings > Expressions and change the engine to Legacy ExtendScript Restart Extensions: If you are using extensions like Mt. Mograph Motion
, simply closing the extension panel and reopening it can reset the "boot" process and clear the error. Identification Tip
on your keyboard to reveal all modified properties in your timeline. Look for red warning banners or properties labeled "Pseudo"—these are usually the source of the "unknown property". Are you seeing this error when opening a specific project applying a certain preset AI responses may include mistakes. Learn more asked to create unknown property of type - Adobe Community
The After Effects error "asked to create unknown property of type" (often followed by "Pseudo") typically occurs when the software encounters a project, template, or preset that uses a custom effect (pseudo-effect) or a plugin that is not currently installed or is outdated. How to Fix the Error Update Legacy Expressions
If you are using an older template in a newer version of After Effects, Adobe's internal changes may cause conflicts.
Action: 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 error is frequently linked to specific third-party tools like Magic Bullet Looks or custom Master Properties/Dropdown Controls.
Action: If the project was created on another machine, ensure all third-party plugins used in that project are installed on your current system. Import into a New Project
If the project file itself is corrupted or stuck in a loop, importing it as a piece of footage into a fresh project can bypass the launch error.
Action: Open a new, blank AE project, then go to File > Import > File and select your problematic .aep file. Remove Conflict-Causing Scripts Some scripts loaded at startup can trigger this error. AEP File Recovery Tool (by AEScripts) – $49,
Action: Temporarily move scripts out of your ScriptUI Panels folder to see if the error persists. You can find this folder in the Adobe After Effects installation directory under Support Files/Scripts/ScriptUI Panels. Rename Conflicting Pseudo-Properties
If you are the one creating the preset, ensure that the names in your pseudo-effect do not conflict with After Effects' internal naming structure (e.g., avoid using general terms like "Layer" as a custom property name). Drafting a Feature: "Property Resolver"
To prevent this in the future, a "Property Resolver" feature could be proposed to Adobe:
Automatic Dependency Check: Upon opening, the system would scan for all custom pseudo-effects and prompt a download/link for missing ones.
Property Mapping Tool: If a property is "unknown," a UI window would allow the user to manually map that legacy property to a new or existing one, rather than just throwing an error and resetting the project.
Safe-Mode Opening: 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:
Did this happen when opening a template or creating your own preset? Are you using any third-party plugins? Which version of After Effects are you currently running? asked to create unknown property of type - Adobe Community
The "After Effects asked to create unknown property of type" error typically occurs when a script or plugin tries to access a property that doesn't exist or isn't compatible with your current version of After Effects. Understanding the Error
This specific error is often triggered by ScriptUI Panels or third-party scripts that attempt to initialize a user interface or background function using outdated or incorrect property identifiers. Because After Effects cannot identify what "type" of property the script is asking for, it halts the process. Primary Fix: Isolate and Remove Problematic Scripts
The most effective way to resolve this is to identify the script causing the conflict: Locate the Scripts Folder:
Windows: C:\Program Files\Adobe\Adobe After Effects (version)\Support Files\Scripts\ScriptUI Panels.
macOS: /Applications/Adobe After Effects (version)/Scripts/ScriptUI Panels. The "Isolation" Method: Close After Effects.
Move all files out of the ScriptUI Panels folder to a temporary folder on your desktop. Reset All Preferences (Nuclear Option):
Relaunch After Effects. If the error is gone, one of those scripts was the "troublemaker".
Move the scripts back one by one, restarting After Effects each time, until the error reappears. This confirms which script is incompatible. Secondary Solutions
If isolating scripts doesn't work, the issue may be related to the Expressions Engine or internal preferences:
Switch Expressions Engine: Some older projects or scripts require the "Legacy" engine. Go to File > Project Settings > Expressions and change the engine to Legacy ExtendScript.
Clear Cache and Preferences: Corrupt temporary files can sometimes lead to "unknown" property errors. Use Edit > Purge > All Memory & Disk Cache to clear the system.
Check Permissions: On both macOS and Windows, ensure After Effects has "Read & Write" access to its own folders. Restricted permissions can prevent scripts from creating the properties they need to function. Common Triggers to Watch For
Outdated Plugins: Ensure all third-party plugins (like Red Giant, Boris FX, etc.) are updated to match your After Effects version.
Font Issues: In rare cases, "Unknown Exception" errors are caused by missing or corrupt fonts that the script is trying to load for its UI.
To help you find a more specific solution, could you tell me:
Did this happen right after installing a new plugin or script?
Does it happen on startup or when you try to open a specific project? What version of After Effects are you currently running?
However, I can offer some general troubleshooting steps and potential fixes that might help resolve or at least help you troubleshoot the issue:
If the error persists in Safe Mode, the AEP file itself is damaged. Here is how to perform surgery on the file.
Ensure your computer meets the minimum system requirements for After Effects. Also, make sure your graphics drivers are up to date, as outdated drivers can cause issues.
Ctrl+Alt+Shift (Win) or Cmd+Option+Shift (Mac) while launching AE.Subscribe now to keep reading and get access to the full archive.