You are working for a longer time with OneNote and you have a new machine.This is great, but you have hunderst of synchronized documents and now, you want to sync them on the new machine.
I really don'nt know what is official way to do this. But, found a workaround, which works great and you need a less time to do it than to find out how to do it.
Here is how it works.
Go to the options of the OneNote on your old machine. Then locate the cache file location:
You will see something like this:
Now go to your new machine, close OneNote, lookup the same folder and rename it to any name of your choise. This is for a case that something goes wrong.
Cope the folder 'C:\Users\YOURUSERNAME\AppData\Local\Microsoft\OneNote\16.0' to the new machine at the same location.
Start OneNote and start syn if not started.
Hope this helps. :)