Failed to Create node 'Categories'


I don’t know the best location to post errors I face in Dynamo, but I was working on a procedure and I’m having issues creating the Categories node.

Failed to load built-in type
Unable to cast object of type ‘Dynamo.Nodes.Categories’ to type ‘Dynamo.Models.NodeModel’.
at Dynamo.Models.DynamoModel.CreateNodeInstance(String name)


i already made a bug report.

if one tries to create a node “categories” an error message shows in the message window.

workaround 1: use an old as template, remove everything but the categories node… everything is working

workaround 2: select the categories in one of your templates go edit/copy. create new workspace and go edit/paste. categories are in the house!

workaround 3: go like workaround 2; create new custom node; paste categories; save. from now you have a custom node that (at least in my enviroment) can be imported any time


Thanks for the update. I’ll give that a try.


Hello Timon and Peter Kompolschek,

“Categories” node is back in action, you can find it in latest daily build.





cool, thanks


I am using the latest daily build ( and it seems that the “Categories” node is still not working at 100%.

Some of the selections seem to give off errors. One example is the Views one. It gives the following error:

Warning: ElementQueries.OfCategory operation failed.
View cannot be a template view.

Another problem related to views is that whenever you have a structural plan (EngineeringType enumeration), the “Document.ActiveView” gives the follwoing error:

Warning: Document.get_ActiveView operation failed.
Unable to cast object of type ‘Revit.Elements.UnknownElement’ to type ‘Revit.Elements.Views.View’.


Thanks for the daily build update. I’ll keep my eyes open for the next one.