Sharepoint open excel in desktop app

Hi everyone,

We have a problem with one of our users. He is unable to open excel files into the desktop app from Sharepoint.
He always gets these error messages:

• The name of the file or path does not exist
• The file is in use by some other program
• The file that you are trying to save has the same name as one already opened

We checked with different sharepoint sites and he always gets this message.

He uses his own private laptop so his PC is not domain joined.
But I do not think this has something to do with it?

We tried restoring Office and also cleared the cache in the %localappdata%\Microsoft\Office\... but this did not resolve the problem.