When trying to open Onenote you may see the error: Onenote can’t start – error code 0x17.
The message will tell you that there’s not enough free disk space, or because ‘we don’t have permission to write to files in your user settings folder’ and follows up with the usual ‘contact your system administrator’.
What if that’s you?
Well the first reason – not enough disk space – is unlikely otherwise Windows would have told you about it, and you’d probably have noticed before now anyway.
The second is closer to the truth, as the cause is likely to be a corrupt or locked Onenote cache file.
To fix the problem, simply navigate to %appdata%\Local\Microsoft\OneNote\15.0 (replace 15.0 with 14.0 if you have OneNote 2010, or 12.0 if it’s 2007) and delete the ‘OneNoteOfflineCache.onecache’ file.
Once done, open Onenote again and it should start up properly this time.