Thanks for the proposal. I did that again, using the appcleaner function of Forklift, though. I did it in two ways:
1) remove the Evernote App and all associated folders in Forklift, and install it again using homebrew
2) remove the Evernote App and all associated folders in Forklift, and install it again using the traditional method, not using homebrew
Unfortunately in both cases the same problem occurs as described in my initial posting!
My notes are still there, as I can verify in the web app and using the iOS app.
Anyone? Any other proposals?