[motdiem]

Thanks cobalt for the link - since 2010 it has migrated to an XML format [1] - which is documented albeit not really human readable.

However, I can't figure out how to retrieve a .one file from the Mac Client to check for the format - anybody knows where it stores its file locally ?

[1] http://msdn.microsoft.com/en-us/library/dd924743(v=office.12...

[scrumper]

Have a look in ~Library/Containers/com.microsoft.onenote.mac/Data/Library/Application Support/Microsoft User Data/OneNote/15.0/OneNoteOfflineCache_Files

Any sandboxed app has its data under ~/Library/Containers/<app>, then from that usually under the Data/Library folder, which is a kind of mirror of your user library folder, just holding that stuff the sandboxed app is allowed to see.

[dunham]

All I see locally is a ".onecache" file - a binary file that appears to contain the notes themselves, and a directory named "OneNoteOfflineCache_Files" of attachments (embedded images, etc.) I don't recognize the header on the onecache file, so I'm guessing it's proprietary.