Does WinXP Pro/NTFS still use a "MBR?"

[Jeff7181]

... or is it called something else? And how can it be rewritten if it becomes corrupt?

 

[MrChad]

AFAIK the master boot record is independent of the file system or operating system.

Yes, it's still used. You can usually restore it by booting to your XP setup CD, entering the recovery console and using the FIXMBR command.

 

[Jeff7181]

Could I use an old Win98 boot disk with fdisk to rewrite the MBR?

 

[loup garou]

Originally posted by: Jeff7181
Could I use an old Win98 boot disk with fdisk to rewrite the MBR?

fdisk /mbr could potentially fix the problem, but could fubar your install. I've had it go both ways. It's a gamble. I'd scrounge up an XP cd and use fixmbr to minimize risk.

 

[Nothinman]

Could I use an old Win98 boot disk with fdisk to rewrite the MBR?

Depends on what was in the MBR before, 'fdisk /mbr' will put back a basic "find first active partition and hand off control to it" MBR, but if you had a more complex bootloader setup fdisk won't help you.

 

[spyordie007]

I'd scrounge up an XP cd and use fixmbr to minimize risk.

:thumbsup: agreed

 

[cleverhandle]

What exactly would change between a Windows 98 MBR and an XP MBR? My understanding has always been that Windows MBR's are just straight-up "hand off to active partition" loaders like Nothinman described. Nothing in that process appears to have anything to do with what OS is being loaded or even what filesystem is being used.

 

[thunderroller]

there is a "fixmbr" tool. use it

 

[loup garou]

Originally posted by: cleverhandle
What exactly would change between a Windows 98 MBR and an XP MBR? My understanding has always been that Windows MBR's are just straight-up "hand off to active partition" loaders like Nothinman described. Nothing in that process appears to have anything to do with what OS is being loaded or even what filesystem is being used.

I mostly meant that fdisk's mbr switch is undocumented and unsupported by MS. The times I used it and f'd up installs were probably my fault, but why risk dealing with something that isn't supported by the manufacturer, if you can get the appropriate tool for the job?

 

[Tennoh]

Don't go under the assumption that /FIXMBR will actually fix the MBR. To be sure, get a disk sector editor, look at sector 00, and check if there's MBR boot code and that there is a 55AA as the last hex code. If 55AA is not there, DO NOT USE /FIXMBR.

What happens if 55AA is not there, /FIXMBR will attempt to write boot code until it encounters 55AA. If that doesn't exist, it will continue to write boot code to more and more sectors, data sectors...

/FIXMBR should never be the 1st thing you do when you have a MBR issue.