Introduction
How to reconnect Notebooks in OneNote
Instructions
Note: Find old Notebook location for reference by looking at the location link structure. This will help you find the notebook while browsing in SharePoint.
OneNote 2016
If your OneNote looks like the image below:
1) Right click on the notebook, click Properties
2) Use the path in Location field to browse in new SharePoint
OneNote for Windows 10
If your OneNote looks like the image below:
1) Right-click on the notebook, click Copy Link to Notebook
2) Paste into Word and click on the linked text (Web View) to go to the old location.
Note: Pasting directly into a browser will not work.
To find your Notebooks in the new locations:
1. Click on the three vertical button 
for notebook, click Open > Open in app
2. Click Launch Application for OneNote or OneNote 2016.