Window XP overwrites MBR when booting (dual-boot Linux / Windows XP)

[Johannes Zellner]

Hello,

XP seems to overwrite the MBR when booting. I installed a dual-boot
box with XP and Linux on different partitions. I'm using a linux boot
loader (grub) which works fine for booting both OS's. But when I boot
into XP the linux boot loader won't load any more afterwards, so my
(reasonable) guess is that XP overwrites parts of the MBR.

1. Did someone experience similar problems?
2. How can I solve the problem?

Any help much appreciated.

 

[Malke]

Hello,

XP seems to overwrite the MBR when booting. I installed a dual-boot
box with XP and Linux on different partitions. I'm using a linux boot
loader (grub) which works fine for booting both OS's. But when I boot
into XP the linux boot loader won't load any more afterwards, so my
(reasonable) guess is that XP overwrites parts of the MBR.

1. Did someone experience similar problems?
2. How can I solve the problem?

It sounds like you don't have Grub installed in the mbr. Double-check where
you put Grub and if it is on a boot partition or /, reinstall it into the
mbr.

Malke

 

[Johannes Zellner]

It sounds like you don't have Grub installed in the mbr. Double-check where
you put Grub and if it is on a boot partition or /, reinstall it into the
mbr.

I do have grub installed into the MBR! grub load w/o problems firstly,
but after booting windows (by grubs chainloader), the MBR is corrupt and
grub doesn't start any more.

Are there cases where windows modifies the MBR?

 

[Pegasus \(MVP\)]

I do have grub installed into the MBR! grub load w/o problems firstly,
but after booting windows (by grubs chainloader), the MBR is corrupt and
grub doesn't start any more.

Are there cases where windows modifies the MBR?

I have been using an MBR-based boot loader for several
years and WinXP Professional never modified it. I know
nothing about Grub but I suspect that your version resides
somewhere other than in the MBR or it requires more than
512 bytes. Boot the machine with a Win98 boot disk before
and after a Windows launch and use debug.exe to examine
and compare the MBR.

 

[Robert Roland]

I do have grub installed into the MBR! grub load w/o problems firstly,
but after booting windows (by grubs chainloader), the MBR is corrupt and
grub doesn't start any more.

I have installed many dual boot machines with grub and XP. I have
never experienced this problem.

Are there cases where windows modifies the MBR?

In my experience, only during install. If I install Linux (with grub)
first, and then XP, the MBR will be overwritten. After I repair grub,
all is well.

Could it be you have an old-fashioned MBR virus?

Maybe you could use SysInternals' Diskmon to find out which process
writes to the MBR?

Does your BIOS provide MBR write protection? If so, you might get an
idea of when the write happens, as it might cause an error message.

 

[Malke]

I do have grub installed into the MBR! grub load w/o problems firstly,
but after booting windows (by grubs chainloader), the MBR is corrupt and
grub doesn't start any more.

Are there cases where windows modifies the MBR?

Windows will always modify the mbr if installed after Linux (or another
operating system) but I have never seen it do this *after* installation. Do
you have two hard drives? Maybe you installed Grub to the mbr on the second
hard drive. In any case, I suggest you post to a Linux newsgroup. Look for
one for your particular distro.

Malke

 

[Donald McDaniel]

Hello,

XP seems to overwrite the MBR when booting. I installed a dual-boot
box with XP and Linux on different partitions. I'm using a linux boot
loader (grub) which works fine for booting both OS's. But when I boot
into XP the linux boot loader won't load any more afterwards, so my
(reasonable) guess is that XP overwrites parts of the MBR.

1. Did someone experience similar problems?
2. How can I solve the problem?

Any help much appreciated.

My suggestion is that you reinstall your dual-boot configuration. To
do this, uninstall both OSes, and install XP on C: as the FIRST
primary partition, then install Linux. Grub will then replace the XP
boot loader.

==

Donald L McDaniel
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