Thanks but MS Onenote 2010 (Desktop) was installed before Onenote App (metro). I did try anyway but this doesn't seem the case. This looks like a known issue and I would hope that one setting in the registry could change it.
I did a local copy of my 5Gb files before doing anything. I turned off Skydrive on my tablet but there was another setting elsewhere that was not taken care of and all Skydrive were deleted on the network. I disabled Skydrive right in the registry.
Guess what ? In my local copy, all the Onenote files (same names) were in fact all shortcuts. I lost everything in Onenote. I'll see tomorrow on my laptop at work, but I am *pissed off*.
Dropbox here I come. It works perfectly with Onenote 2010. No insanity.
Microsoft messed up a nice thing AGAIN. My Skydrive days are OVER.