MBR changes keep reverting back to the previously set version

#1
Hello everyone, I have been googling for an answer to this and it is really bothering me now, so I thought I would ask instead.

I have Windows 7, and I recently installed Windows XP to it's own partition. Setup was fine and after the install XP worked gloriously. During XP I set the MBR to how it is in this screenshot.

Untitled.png

After some googling and egg thrown on my face, I discovered that of course, as always with XP, now it will not boot. It complains about "NST/ntldr" or along those lines and an error code 0x000..0f. After more googling I discovered that this NST folder is on my C Drive, not my XP install drive as mentioned in a different guide. So I removed the boot option and added it with auto configure, wrote to the MBR, rebooted and it still didn't work. Turns out when I re-opened EasyBCD, it never changed at all! *Dun dun dun!*

Does anyone know what could cause this? If I point the XP option to any other drive and reboot it will keep that configuration, just not on the C: drive. Any help will be appreciated, I'm sick of using the Windows 7 restore disk just to go around in circles.

the XP partition is definitely functional, it just seems the boot option refuses to be corrected... Story of my life. I'm off to college, I'll keep an eye on this thread and I have Teamviewer in case anything is needed.
 
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Terry60

Knows where his towel is.
Staff member
#2
You seem to be confusing the MBR and the BCD.
Don't "write MBR", if that's what you've been doing.
Add an XP entry to the BCD.
That's it.
Finished.
If you restore the bootloader with write MBR, you then go back to square one in an infinite loop of adding and removing the same entry.
EasyBCD Basics - EasyBCD - NeoSmart Technologies Wiki
 
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#3
I see, so I have been trying to change the boot partition and then rewriting which MBR to use? I mistook Write MBR as writing records into the MBR and not the MBR itself, although come to think of it that makes a lot of sense. I will try it later when I am at home, I must of misread a guide on how to use the program. Thanks for clearing things up.
 

Terry60

Knows where his towel is.
Staff member
#4
"Write MBR" is only ever needed in the specific cases where a "foreign" (to Vista/7/8 boot) system like XP or Linux has been installed after Vista/7/8 and has taken control of the boot process.
Then, you would use it (once only) to put the Vista/7/8 boot manager back in control.
The BCD is W7s repository of information about any multi-boot OS which appears in the boot menu. It's the equivalent of XP's "boot.ini", but it's not a text file, so it needs BCDedit command-line experience to manipulate it, or preferably the EasyBCD GUI to handle it for you.
The MBR is a completely different link in the boot chain.
Have a read of this excellent informative guide if you want clarification.