grub2-mkconfig hangs - because os-prober hangs. Some mount.ntfs processes were hanging. After killing them hardly I can do: [root@dev-mk ~]# mount /dev/sda2 /mnt The disk contains an unclean file system (0, 0). The file system wasn't safely closed on Windows. Fixing. - and it will hang. I would expect os-prober to do probing in such a way that external failing or hanging tools didn't stop the probing ... and if other tools are considered essential then it should show the output from them so debugging was possible. os-prober-1.51-1.fc17.i686 fuse-2.8.6-4.fc17.i686 ntfs-3g-2012.1.15-1.fc17.i686 kernel-PAE-3.3.0-8.fc17.i686 or kernel-PAE-3.3.1-5.fc17.i686
IMHO it is too unrealistic to expect os-prober to be prepared that "every external program might hang"! Maybe mount.ntfs is really not expected to hang and a bug against it instead? Another thing which comes to my mind is to mount partitions read only. It might prevent mount.ntfs from trying to fix the problem completely as I can see in its man page. If your partition is still unclean, can you try mount with -o ro option to see if it doesn't hang?
I can confirm this behaviour, similar situation but fuse-2.8.7-1.fc17.x86_64 kernel-3.3.2-1.fc17.x86_64 Partition was unmounted cleanly, but now it cannot be mounted even read only: mount.ntfs -o ro /dev/sda1 /mnt hangs (10+ minutes) in fuse_get_req. In f16 os-prober and mount work as expected.
I really think that this bug should be assigned to ntfs-3g or fuse rather than os-prober.
*** This bug has been marked as a duplicate of bug 812798 ***