Custom Properties Error

In some cases, the path stored in the Custom Properties might get corrupted. This can happen for instance if you rename the objects, materials or shape keys they are pointing to.

Most of the time, the issues are not impacting the functionalities, but might create issues if you use tools such as Rebuild Custom Properties and Clean Model, as they rely on the saved paths to correctly restore or remove the drivers.

The error is notified in both the Custom Properties list and in the single custom properties settings (from MustardUI 2026.4).

How To Solve the error

When this error appears, you might want to correct the path.

• Look at the path and try to understand what part might have been changed

Example

For instance

bpy.data.materials["Tifa Head"].node_tree.nodes["Math.003"].inputs[1]

might have the wrong material name "Tifa Head", or the node "Math.003" might have been renamed in the Shader editor.

• Click on the pencil icon on the right, and correct the path.

To speed up the debugging process, enable Python tooltips in Blender settings.

Which will allow to see the whole path of Blender properties if you put the model on top of that property.

Moreover, you do not need to manually write paths (which can also lead to typos). Just right click on the property and copy the full data path.

Important: if you use this method, remove the last dot and the final path specification.

# Copy-pasted from Copy Full Data Path: Wrong!
bpy.data.materials["Tifa Head"].node_tree.nodes["Math.003"].inputs[1].default_value
# Correct (stripped of the last specification)
bpy.data.materials["Tifa Head"].node_tree.nodes["Math.003"].inputs[1]