I'm stuck in the Busy Box shell after upgrading from Ubuntu server 11.10 to Ubuntu server 12.04 64 bit. During the booting phase the system hangs while mounting root filesystem. My system is so configured: /dev/sda1 -- /boot /dev/mapper/vg-lv_root /dev/mapper/vg-lv_var /dev/mapper/vg-lv_tmp When the boot process fails and I'm forwarded to the busybox shell, if I type vgchange -ay I can mount my volumes and all it's OK. But it does not enable LVM automatically so that it is impossible to mount root, var, and tmp. I tried to start with a Knoppix, chroot, reinstall (aptitude) both kernel and lvm2 as suggested by this tread "Fixing unbootable installation on LVM root from Desktop LiveCD": nothing changed. I can't figure out what is the problem. Any suggestion is welcome. Thanks in advance.