GNOME Bugzilla – Bug 586910
MBR does not reflect the GPT partition map
Last modified: 2012-06-09 21:05:55 UTC
Please describe the problem: Sometimes when GParted is used to modify partitions on a Mac, it changes the GPT but not the MBR. So the MBR does not correctly reflect the new partition map. Since the GRUB bootloader relies on the MBR being correct, this renders Linux completely unable to boot. It also makes Windows incapable of booting. This bug is well documented on Apple architectures. I don't know whether it exists outside of Apple. After using GParted, it is necessary to run a utility program to 'resync' the MBR and GPT records of the partition map. Steps to reproduce: 1. Modify the partition map using GParted 2. Attempt to reboot into any partition that has been modified using GParted. 3. Get an error. 4. Examine GPT and MBR records using gptsync.efi within rEFIt. 5. Notice that they are different. Actual results: Expected results: Does this happen every time? Other information: See here for rEFIt's discussion of these concepts, particularly at the very bottom: http://refit.sourceforge.net/myths/
Thank you Richard for reporting this problem. To perform partition table manipulations, GParted uses the libparted library from the parted project. http://www.gnu.org/software/parted/index.shtml Would you be able to report this problem to the parted team? That way all projects that use the libparted library would benefit from repairing this problem.
Okay, done.
Thank you for reporting the problem upstream. Hopefully the parted developers will be able to address this problem soon.
Following is the link to the bug report that Richard posted: http://lists.gnu.org/archive/html/bug-parted/2009-07/msg00002.html There is also a enhancement ticket requesting support of MBR+GPT hybrid partition tables: http://parted.alioth.debian.org/cgi-bin/trac.cgi/ticket/190
There has been some activity in the parted project regarding hybrid GPT/MBR partition tables: Re: Bug with rewriting partition table - need help http://lists.gnu.org/archive/html/bug-parted/2010-02/msg00006.html Parted Bug Report: Partition table rewrite even after read-only operations (particularly, it destroys MBR part of hybrid GPT+MBR table): http://parted.alioth.debian.org/cgi-bin/trac.cgi/ticket/250
Many enhancements have been made to parted in the area of GPT support since this bug report was opened. Would you be able to test the problem with the latest GParted Live 0.5.2-1 which includes parted-2.2?
I'm not in a position to do so right now, sorry. Could someone else give this a try? You could also ask the guys on irc.freenode.net on #ubuntu, since they use gparted all the time. Richard
Thank you for your response Richard. Since I do not have Apple hardware to test with, and since I am working on many other bug reports, I often rely on people like yourself to check if a bug is fixed. If you are unable to test or find someone to test, then this bug report will have to wait until someone is available to perform the testing.
I would be willing to test this.
Hi reeves.87@gmail.com, If you could test this it would be much appreciated. If the mismatch between the MBR and the GPT still occurs, you can use rEFIt to repair the problem. http://refit.sourceforge.net/
This is fixed in parted-2.3. Don't know about parted-2.2.
That is excellent news! Thanks for the testing reeves.87@gmail.com. GParted Live started bundling parted-2.3 as of testing release version 0.6.0-7. Hence this problem should now be resolved with stable releases of GParted 0.6.3-3 and higher. In other words the problem is solved with the latest versions of GParted Live. Closing this bug.
The command line program gptsync has been included in GParted Live 0.12.1-5. You can re-sync the GUID Partition Table to the MSDOS partition table with the following command: sudo gptsync /path-to-disk-device Where /path-to-disk-device is something like /dev/sdb