
Hi Levi,
You didn't do anything wrong, that's a classic OneNote sync churn after a big re-org.
When you copied sections into a new notebook, OneNote had to reconcile several large, similar trees at once. If it can't find the matching section file on the server during that process, it parks a local copy under "Misplaced Sections". Those aren't duplicates you should trust, they're unsynced local placeholders that stay there until you move their pages into a real, cloud-backed section or delete them.
The "server is full" message comes from the cloud side, not your PC. It usually means your OneDrive/SharePoint quota was hit or a OneNote store limit was tripped. OneNote will refuse to sync when the service reports Quota Exceeded (error 0xE0000796
), and Microsoft specifically calls out checking your OneDrive/SharePoint storage and making sure the notebook isn't oversized. OneNote notebooks also have a 2 GB limit for the single notebook file in the service, so very large notebooks or sections stuffed with PDFs and printouts can push you into this state.
Try this way to get stable again without losing notes:
First, stop moving anything for the moment and pick one PC as your "repair workstation". Sign into OneDrive on the web and confirm you actually have free space. If you're close to your quota, free some space or temporarily move large non-OneNote files out so OneNote can breathe. If you're on a school account that uses SharePoint, ask IT to confirm your quota there as well. Once quota is healthy, create a brand-new notebook on the web so you have a clean cloud "target". That new notebook guarantees a good server home for the content you keep.
Back in the OneNote desktop app on that PC, open the new notebook alongside your original notebook and the "Misplaced Sections" container. Use File > Info > View Sync Status to keep an eye on progress as you go. Now move pages in small batches into the new notebook rather than dragging whole sections at once. After each small move, give it a moment and confirm the green check or "Up to date" state. If a page won't load or sync, the culprit is often a huge printout or embedded file.
Microsoft's guidance is that oversized content can block syncing and even throw "file too large" errors. When that happens, re-insert the material more lightly: split a giant deck into several smaller PDFs, insert them page-range by page-range, or attach the PDF as a file (or link to it) instead of embedding the entire printout. This keeps the OneNote section files small enough to sync reliably.
Work steadily until everything you care about lives in the new notebook and you can also open and read it at OneNote for the web. When the web view shows the latest changes, that’s your confirmation you’re protected by the cloud. At that point, close the old notebook(s) in the app so they don’t keep churning, and only keep the new notebook open on all devices. If you discover something seems "missing", you can still recover from the local OneNote cache on the repair PC. Microsoft documents how to harvest pages from the cache so you can move them into your new cloud notebook. Do that before you clear any cache or uninstall the app.
Please, let me know how it goes!