This comprehensive troubleshooting guide breaks down the core technical causes behind this error and provides actionable, step-by-step solutions to repair your project files. What Causes the "Unknown Property of Type" Error?
Corrupted preferences can cause a variety of issues.
Hold down Ctrl+Alt+Shift (Windows) or Command+Option+Shift (Mac) while launching the program. An expression referencing thisComp
Ensure all layers and effects referenced in your code match their current names exactly.
| Step | Action | |------|--------| | | Hold Ctrl+Alt+Shift (Win) or Cmd+Option+Shift (Mac) while launching AE → click “Delete Preferences” | | Clear cache & database | Edit > Purge > All Memory & Disk Cache | | Disable “Allow Scripts to Write Files” | Edit > Preferences > Scripting & Expressions → uncheck the option, restart AE | | Run Adobe Cleaner Tool (if error persists across reinstalls) | Download from Adobe – removes corrupted extensions/scripts | An expression referencing thisComp
Corrupted application memory data blocks will persistently call up non-existent property configurations.
An expression referencing thisComp.layer("Solid") but the layer has been renamed, deleted, or pre-composed. An expression referencing thisComp
After Effects will treat the old project as a folder asset, frequently bypassing the structural script loops that trigger the startup crash. Save this as a new file. 2. Re-Naming and Fixing Custom Pseudo Effects