Hello. I have a problem with the Dynamo background showing an error when opening (see screenshot). When I close Dynamo, a fatal error appears and closes Revit (I’m on Revit 2020.2.3, Dynamo Revit 2.3.0.8352, and Dynamo Core 2.3.0.5885). Has anyone ever had this error and how did you fix it? I did not find answers on the internet. Thank you very much.
Hi @Sarah.Meslem,
It could be a conflict with a plugin.
However, I had the exact same problem a few months ago after updating several packages with zero touch nodes. New versions of these packages fixed this problem.
Thank you @Alban_de_Chasteigner, I will try to uninstall all the packages. In the meantime I switched to Revit 2021 and Dynamo 2.6, and I no longer have this problem. Too bad all our projects are not on Revit 2021 yet, but it will come 
I removed all the packages i loaded in Dynamo 2.3 and it works much better, thanks! There must be one causing the problem (or at least one…)
I did several tests loading the packages one by one and couldn’t find which one was causing the error.
It can therefore be the association of 2 specific versions of 2 packages.
Fortunately the latest versions of these packages no longer cause this problem.