Recently, I faced
this issue in my Ubuntu version installed inside Windows using Wubi.
The first screen you are going to see will be like this if you also
met with this problem,
Then to make sure
this is the same issue boot in to your Windows and browse to the
drive (I will refer it as G:\) where your Ubuntu is installed and
check whether you have G:\ubuntu\disks\root.disk
file. May be you will miss this particular file or the \disks
directory itself, this will make sure you are also experience the
same issue as me. Solution is simple and I found it from official
wubi guide. What has gone wrong here is that due to a incomplete
Windows shutdown the files needed by Grub is missing (have been moved
to a hidden folder in Windows). These missing files can be found in a
directory called G:\found.000. So
the solution is to copy your missing file or whole directory to the
correct directory structure back. Here is the solution.
Just
copy and paste the file to make the directory structure like
G:\ubuntu\disks\.
You
are good to go and boot from your Ubuntu :)
