Jean, thank you : i confirm the apparent problem (freeplane not calling onenote) and the solution (removing the "section_id" part of the URL onenote creates. fact is: this might have to do with the way freeplane escapes links in urls, since otherway the links created by onenote dropped - for instance - in a web browser, do work without taking out parts. I have looked into the freeplane options and I have found that the call to the browser (which could - i suppose to - be the delegate for opening...