This question on askubuntu is about the
error: malformed file
Not only here on askubuntu, but everywhere else I've been reading about it, this is considered certain to be a GRUB issue. I thought it might help if I'd tell you how it got to it: I'm running an "Igel 5/4 thin client" as a DLNA (UPnP) Media Server. I installed Lubuntu 14.04 i686 (for that's the 'lightest' Ubuntu distribution I had that day). I generally use ssh to install, configure and test things. After everything met my needs I decided to get rid of lxde and followed this little guide exept that I had to use nano instead of gedit for I was on ssh. Then I did a
sudo shutdown -r now
as usual and waited for my script 'espeak'ing to me about the current server state and network config. But it didn't. after three tries to reboot the machine I plugged a monitor in and was presented the above error message.
I hope that'll help a bit