je pense avoir trouvé la solution :
http://fedoraproject.org/wiki/Bugs/F8Common
Bug n° : Bug 372011
https://bugzilla.redhat.com/show_bug.cgi?id=372011
je vais essayer de rajouter : "updates=
http://katzj.fedorapeople.org/updates-f8-yumloop.img" lors de l'intallation
Merci pour vos reponses
Bug 372011 - Anaconda hangs resolving dependencies on upgrade.
Users with packages installed from other repositories can have their upgrade hang while resolving dependencies for the upgrade. Rebooting at this point is safe and will not leave your system in an inconsistent state. An update image is available for the problem at
http://katzj.fedorapeople.org/updates-f8-yumloop.img. There are three ways to use this image:
If you have a network connection, the easiest is to add "updates=
http://katzj.fedorapeople.org/updates-f8-yumloop.img" to the kernel command line.
If you don't have a network connection, you will need to have a partitioned USB key and then place the update image on the partition of the USB key and boot with "updates" added to the kernel command line.
The Fedora Unity Re-Spin has the image incorporated on the ISO images, look at
http://spins.fedoraunity.org/spins
To confirm that the fix is in effect, you can switch to tty2 and ensure that there are files in /tmp/updates.
New CD boot images (boot.iso) will be available in the near future with the fix for this integrated and will then be linked here.
