The "After Effects error: asked to create unknown property of type" typically points to missing plugins, corrupted preferences, or legacy expression conflicts. This often occurs when opening project templates or presets designed with third-party tools that aren't currently installed. Common Fixes
If you want, paste the exact error message, AE version, OS, and list of installed third‑party plugins (or attach the small problematic project). I can give targeted steps for that setup.
Reset Preferences: Corrupted preference files can cause unexpected property errors. Reset them by holding Ctrl+Alt+Shift (Windows) or Command+Option+Shift (macOS) while launching After Effects. The "After Effects error: asked to create unknown
If the error is caused by an old template, you can often fix it by converting the expressions to the modern engine: File > Scripts > Update Legacy Expressions.jsx Alternatively, go to File > Project Settings > Expressions and change the Expressions Engine to Legacy ExtendScript 2. Troubleshoot Scripts and Plugins Isolate Scripts : Remove scripts from the ScriptUI Panels
: Sometimes conflicts with the GPU can cause property errors. Try switching your renderer to Mercury Software Only File > Project Settings > Video Rendering and Effects Check the script’s compatibility – does it match
If the error repeats infinitely:
This error usually happens when After Effects tries to load a pseudo-effect, script, or preset that it doesn't recognize or that was created for a different version. It’s common when using older templates or third-party plugins like Red Giant Universe. paste the exact error message
If the error occurs upon launching After Effects, a script in your startup folder is likely the culprit.