Life, toss and turn! Windows XP, Vista, 7, 8, 8.1, 10, Black Apple, Ubuntu, Ubuntu Kylin, Deepin, Phoenix OS, Peer OS, Elementary OS, centOS, I finally messed up my new computer and had the biggest problem ever. I could not enter the system directly through the boot interface, and the black screen showed “Error: Unknown filesystem grub rescue “, in line with fine asked baidu, on the Internet a lot of, the mainstream approach very much the same but more or less problems, where some of the replacement is not clear, in a move not bottom go to, the combination of routine summed up the solution is as follows: a method, a

baidu experience on this post can basically solve the problem of less serious:
http://jingyan.baidu.com/article/c85b7a640cd7d6003bac95f8.html,
with step 3 should pay attention to the “ls (hd0, msdos1)/boot/grub” should be add a space after the ls,
the “ls (hd0, msdos1)/boot/grub, if each tried, but it is always display the error: The unknown Filesystem, or filesystem, is the only option;
2, method 2
operation on WinPE, first make usb boot disk, choose the most simple fool operation, on the baidu search U disk boot disk, conveniently take the first http://www.kuaiqidong.com/ search results, in fact, the startup disk production tools are the same, download and install, fool operation, if not true, there will be tutorials on download site, made after startup disk into the computer, in holding down the F10 boot directly into the boot option (some computer will be different, Here don’t enter BOIS modify priority startup), choose your usb flash drive, and then select the third item on the interface, enter the PE system, on the surface of the table there is a practical tool folder, choose “partition tool DiskGenius”, the top row labels “hard drive”, select “rebuilding the master boot record (MBR)”, then click “yes”, then pull the usb flash drive to restart to go, but sometimes will appear below this kind of situation, such as my computer is SSD + mechanical hard disk this model, I carry the Windows on the SSD and my second system in mechanical hard disk, After entering the “Partition tool DiskGenius”, select the disk with the second system in the left bar, and then click “hard Drive”… According to the above steps, restart will let you choose which launched a system, but there is a problem is to let you choose the first option is winpe what of, the name is too ugly, you can refer to this item according to be fond of change the boot name:
http://jingyan.baidu.com/article/22a299b5223ecc9e19376a11.html.
So far the problem has been solved perfectly! As to how to delete the double system under Windows system in another system may follow:
http://jingyan.baidu.com/article/642c9d34e371c3644b46f768.html.
In the end, I would like to advise you that it is enough to install a Windows system for work, study and entertainment.