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rhood 05-05-2012 12:45 PM

after multi-boot install, windows no longer boots from grub
On a macbook pro 8.2 (2011), I had triple-boot working with macos, windows 7, and ubuntu 10.04. My partitions are as follows:
/dev/sda1 fat32 /boot/efi (I think macos uses this to boot)
/dev/sd2 unknown Macintosh (this is the main mac partition)
/dev/sda3 hfs+ Recovery HD (mac recovery)
/dev/sd4 htfs Bootcamp (windows partition, set up by mac bootcamp)
/dev/sda5 ext4 / (ubuntu partition, which I created after installing windows)

Macos has its own boot system. If I hold down alt/option, I can select the mac partition and it boots that. Otherwise, it went to the grub menu after a few seconds and I could select either windows or linux and either would boot just fine.

I installed ubuntu 12.04 over the previous ubuntu 10.04 on /dev/sda5 (and told it to install grub on that same partition which I think is what I did when I previously installed 10.04), it installed fine and both macos and ubuntu work just like they did before. But when I select windows from the grub menu, I just get a blank screen with the message "error: not a valid root device. Press any key to continue..."

When I press a key (or wait a few seconds) it just takes me back to the grub menu.

I've been looking around for hours but can't find the solution. Any ideas how to fix this? Thanks in advance.

widget 05-05-2012 05:21 PM

Run this from a live CD and post the results.tex(complete) here. You will need to post that from the Live session as the results will show up on the Desktop.

rhood 05-06-2012 11:46 AM

1 Attachment(s)

Originally Posted by widget (Post 4671225)
Run this from a live CD and post the results.tex(complete) here. You will need to post that from the Live session as the results will show up on the Desktop.

Thanks for your response. I am attaching the RESULTS.TXT

widget 05-06-2012 09:57 PM

OK, I think this is a pretty easy fix.

First I must say that I have no experience with Mac or hfs+.

But the results.text seem to indicate that everything is all right. You have menu entries for both Mac and MS.

The problem seems to come from when you installed. Your 10.04 grub was, as it needs to be, installed on the MBR (sda not sda5). It is still there and looking for the source files in your now gone 10.04 install.

You will need to correct this problem.

Read that section of that site. Will give you several options using the LiveCD. I have never used the graphical tool in the Live Session. I have always chrooted in and used just run the commands. I hear the graphical tool works though. Quit using Ubuntu before that came out.

If that does not work just continue on in that same section and it will give you instructions for using the terminal. Note that you do have the results.test and that gives you all the info on the partition you are installed on (sda5) and you only have sda

This should straighten you out.

The only thing that concerns me is that you seem to have files for grub-legacy also. This could through a monkey wrench in the works. This can be dealt with if it is a problem.

Give the direction on that link a try. It is easy and should work. If not we will approach it another way.

rhood 05-07-2012 07:16 PM

Thanks. I can now get to all 3 OS's if I hold down alt/option during boot and select either mac (goes directly to mac os) or "windows". "windows" takes me to the grub menu and from there I can select either ubuntu or windows and both will load just fine now.

I'm not sure why all the instructions I could find for triple-booting macbook pro like this said to install grub onto the linux partition instead of MBR. Also not sure why it seemed to work with 10.04 but not after installing 12.04. In any case, I now have access to all of my OSes, and really appreciate your help getting that to work. Thanks again.

widget 05-07-2012 10:39 PM

That is great. It is a real pain when things don't boot.

You should mark this solved. Top of page under Thread Tools. Only the OP can do that.

Makes it easier for folks useing a Forum Search if they have a similar problem to find threads that may have a solution for them.

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