You may be experiencing the same issue as discussed here: https://www.reddit.com/r/OneNote/com...l_of_my_notes/ MS OneNote are aware that something is amiss. I found that as soon as I opened ON, it synced and then the entire section disappeared, leaving nothing. If you open the notebook online, choose 'Edit in OneNote' from the top and select the locally-installed application, then the missing section gets copied back and everything seems to be restored. Not sure for how long, though, until the problem gets fixed. It was a relief to find the online version was still intact. bob