Je n'ai pas disk burner ou iTunes.
Par contre, j'ai trouvé la solution, ou plutot l'explication :
http://www.macfixit.com/archives/april.01.a.shtml#toast-04-04
Toast Titanium & Apple SuperDrive: cannot create DVDRs
Version 5.0 of Toast Titanium cannot burn data to a DVD in the DVDR format.
Roxio's Toast FAQ <
http://www.roxio.com/en/products/toast/toastfaqs.html>
states that Toast supports Apple's SuperDrive. But until version 5.01 is
released, data support is limited to writing CDs. Attempting to burn a DVDR
will result in a "..can't determine free space on disk" message. Evidently
Toast is able to write data to an 'older' Pioneer DVD/CD mechanism, however,
that mechanism is not used in SuperDrives. Mike White writes: "A tech in
Pioneer support informed me that I must be using an old build of the product
as the error was fixed in the new version of Toast 5. Apparently he had a
prerelease version, because Roxio told me that DVDR support would not appear
until 5.01 is released."
Voila.
Il va de soi que j'ai lu le manuel et été voir sur le site