I have already installed Revit from scratch and it doesn’t solve the issue.
I found that deleting the folder “2.6” from the appdata under the Dynamo Revit, fixes the problem temporarily but then it goes back. Any guess?
Haven’t installed anything new on my machine
Looks like it’s failing to find your geometry library, likely due to a bad combination of installs on your host app.
Be sure that all Revit updates are installed as a first step. Should be 2021.1.3 if I am not mistaken.
Reinstalling Dynamo will often fix this error (assuming that everything else is working as expected, as Jacob mentioned.)
I found the problem is in the way we are using PyRevit to load the ProtoGeometry library.
For your information, reinstalling Dynamo (which means reinstalling Revit) does not fix the problem in this case. The only way is to dele the folder 2.6 in AppData.
Thanks anyway.