After Effects Error Asked To Create Unknown Property Of Type Fix -

The Adobe Support Community and forums are great resources. Someone else might have encountered the same issue and found a solution.

If this error appears immediately after running a script (like a motion graphics toolkit or a rigging tool):

The .toFixed() method in expressions can confuse After Effects when fed non-numeric values. The Adobe Support Community and forums are great resources

Bad expression that can cause "fix":

// This can trigger the error if x is undefined:
x = thisComp.layer("Null").effect("Slider")("Slider");
x.toFixed("fix"); // Incorrect usage

Fix:
Search all expressions for .toFixed( and ensure the argument is a number. Replace toFixed("fix") with toFixed(2). Fix: Search all expressions for

To check all expressions at once:
Edit > Find → Search for toFixed( → Check the box "Search in Expressions".

If nothing else works, you might consider uninstalling and then reinstalling After Effects. If nothing else works, you might consider uninstalling

This is a data mismatch or corruption error. It typically occurs in three scenarios:

If the error happens spontaneously or when opening a specific project, your preference file may be corrupt.

If you have tried every method above and the error remains, use these last-resort techniques.