
Let me develop the process through which I think I get out of the problem - Open the rotten notebook and immediately suspend the synchro to avoid OneNote to crash - Right-click on a section tab and choose Export. Select "Full notebook" and the .onepkg format in order to extract your full notebook on a local disk (choose a significant name, ie OneNoteBackup.onepkg) and validate. The extract process can be long and ou may have error messages related to unsync pages, continue anyway. - close the old and rotten notebook - Create a brand new notebook somewhere else on the OneDrive (ie MyNewOneNote) - open the OneNoteBackup.onepkg you just created - For each section of the OneNoteBackup.onepkg notebook, Right-click on the section tab, and choose the option "Move or Copy" (this is an approx translation while I use the french version of OneNote). In the next screen, select the MyNewOneNote notebook and click on the Copy button (be sure to select Copy and not Move in order to keep your backup unchanged, just in case...) - when all the sections have been copied to the new notebook, close the OneNoteBackup.onepkg notebook. - on the other PC, close the old and rotten notebook and open the new one - In the end, check that the automatic synchro is active on both PCs. Your problem should be fixed, in my case, It worked