Im experiencing the same behavior, after updating to the most recent version (6.13.14.7474 (307474) Public (CE Build ce-48.0.5483)) on Windows 7. After a sync I see my content, but as soon as I select the note, it disappears. I do see the content on the web, have rebooted, but no change in the behavior. There was no "crash" in my case as another user had experienced, just a version update.