I have been having this strange problem for a month or so. I have installed Ubuntu 14.04 alongside Win8.1 on my Lenovo z510. It worked fine for about 5 months, but almost a month ago, I started getting error at the grub menu in grub grub rescue>filesystem is unknown. Sometimes I also used to get a error:trying to read/write outside hd0 or similar.

A workaround was a few restarts, or a manual set of root and insmod normal from the rescue prompt was to be done. I got fed-up with this and overwrote grub with the windows bootloader. This time, it worked(although it boots directly into Windows). I never got any error while booting. Yesterday I reinstalled ubuntu hoping it will work again but it is just like before. Anyone has any ideas/solutions on how to get ubuntu working?

  • Is your system using UEFI BIOS? You might want to make sure SafeBoot is disabled if you're dealing with one. – Ian Jul 25 '15 at 6:22
  • It is but both the OS are installed as Legacy. And SecureBoot is disabled too – blumonkey Jul 26 '15 at 7:37

Try Boot-Repair

Live Boot the ubuntu and install it or use ubuntu secure remix which have with boot-repair in it. Connect to internet white working with Boot-repair.


  • I have already tried that. It gives the same result. – blumonkey Jul 26 '15 at 7:37

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