I just encountered Grub Error 13 and Grub Error 17 for seemingly no reason. I fixed the problem and thought I could save others undue headache by explaining my fix here.

Note: if this tutorial doesn’t help you, possibly because fdisk reports your known Linux partition correctly as Linux, you might also try my Grub Error 13 with Grub Error 17 tutorial.

I just had an interesting time with trying to boot into Linux on my PC. Last night, I noticed my /boot/grub/menu.lst file had gotten overwritten when I performed some Ubuntu updates. This meant I had to add in configuration to allow Windows to boot, and since I didn’t have a backup of my old, working configuration–mistake number 1–I looked online. I found something that looked like it would work, even though it had Grub’s hide and unhide commands in the configuration–mistake number 2. I rebooted and successfully got into Windows.