The result references a tool  that is no longer valid. Invalid tools will  show an invalid tool symbol 
, invalid script 
, or invalid model 
. The tool either cannot be
opened or does not exist. Some causes of this error include
- A model might be using an invalid tool or may use another model that cannot be found or is invalid.
 - If the tool is a custom tool built by a third-party developer, the tool may not exist in a toolbox, may have a problem with the tool's implementation, or it may not have been registered appropriately at the time of sharing.
 
Solution
For steps to repair an invalid model tool, see Repairing a model.