If the project file itself is slightly corrupted, you can often bypass the error by importing it into a fresh workspace rather than opening it directly. Open After Effects and create a brand new project. Go to File > Import > File. Select the problematic .aep file.
If you’ve been working in Adobe After Effects long enough, you’ve probably seen a few head-scratching error codes. But the one that has been popping up more frequently lately—especially for users working with expressions, templates, or specific third-party scripts—is:
: Go to File > Scripts > Update Legacy Expressions.jsx to fix older expression syntax that might be confusing the newer engine .
The infamous "unknown property" error in After Effects!
This violates Adobe’s support terms, but it has saved many projects. Backup the original first.
Open a new, empty After Effects project. Go to File > Import > File and select your corrupted project. This often allows you to recover your compositions without triggering the property error. 5. Switch Expression Engines