Did this happen a new plugin or script?

The .toFixed() method in expressions can confuse After Effects when fed non-numeric values.

To fix the , you must address outdated expressions, missing third-party plugins, broken ScriptUI panels, or script syntax mismatches.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.

Think of it like trying to install a car part on a vehicle that isn't designed for it—the instructions might be clear, but the underlying model just doesn't have the necessary mounting points. Understanding the "why" is the first step toward a fix.

If the error explicitly references a missing effect or third-party plug-in framework (such as Red Giant or Boris FX Continuum), the data fields cannot map correctly.

Did this error trigger while , launching the app , or running a custom script ? What version of After Effects are you currently running?

Corrupted preferences can cause a variety of issues.

If a specific project file won't open, importing it into a fresh project can bypass corrupted startup metadata.