Cannot create new notebooks

I get the following error:

 line 106, in _get_schema_json with open(schema_path) as f: FileNotFoundError: [Errno 2] No such file or directory: 'c:\\users\\ernesto estevanell\\appdata\\local\\programs\\python\\python36\\lib\\site-packages\\nbformat\\v4\\nbformat.v4.3.schema.json'

The file do exists…
Pls help

There was a bad release for nbformat – try pip install -U nbformat and rerunning.