Did you manage to get it resolved? I have the same problem - upgraded to the new version, but the wheel keeps spinning indefinitely. Tried to uninstall and get the new version from the website, but the problem remains.
I also tried re-installing the old version, but now my notes are a "view only" and I can't edit them. Then I tried upgrading to the new version through the deksktop app, and now 80% of my notes are missing.
This is frustrating to say the least. The in-web version seems to be working though...
If anyone has any suggestions/help, it would be greatly appreciated.