The unknown filesystem solution appears when Windows 7 and ubantu are enabled.

When Windows 7 and ubantu are enabled, the unknown filesystem error occurs. The method is as follows; grub rescue> lsgrub rescue> ls (hd0, 1) if an error occurs, use grub rescue> ls (hd0, msdos1) when the information displayed in a partition is different from that in other partitions, it is determined that ubantu is in this partition. For example, we assume that (hd0, 5) and then grub rescue> root = (hd0, 5) grub rescue> prefix =/boot/grubgrub rescue> set root = (hd0, 5) grub rescue> insmod normalgrub rescue> normal enter Start Menu www.2cto.com press C enter command line grub> set root = hd0, 5> set prefix = (hd0, 5) /boot/grub> linux/vmlinuz root =/dev/sda5 (you cannot press the tab to get vmlinuz)> initrd/initrd. img> boot: Enter sudo updategrubsudo grub-install/dev/sdaok on the terminal to complete the process by Wu shuqiang 123.