I have this problem too. I see the spinning baseball all the time. It has almost become unusable. I have premium support and they have been of limited help with multiple tickets. Reinstall, send logs, wait, no real improvement. I've started using one note and I'm considering a complete migration because this issue has existed for 6 months or more. I don't think they have much of a development team left, because each release has more problems than the previous one.