What partition does "Write MBR" write to?

On "BCD Deployment" tab, there are two functional groupings, "Create Bootable External Media" and "MBR Configuration Options". The first grouping includes specification of a partition to which the "Install BCD" operation will be applied. The second grouping allows one of two boot loaders to be written when "Write MBR" is selected, but does not include a partition specification. Does the "Write MBR" function always operate on the current boot partition, or does it operate on the partition selected for the "Install BCD" operation? Hopefully, it operates on the selected partition.


Knows where his towel is.
Staff member


New Member
Terry, i think the OP is referring to making a new MBR in EasyBCD - the option for rewriting the MBR

As he said - which DRIVE (he meant?!!) is going to be "re-MBR'd"

i have the same Q - if using USB drive "H" - loaded it's /boot/bcd store - and i say - want to make this 'H" drive boot - active flag and new MBR - WILL IT write to H or somewhere else?
Because my main PC boot drive is C and i dont want its MBR affected.

Asking is safe = better than sorry.


Knows where his towel is.
Staff member
The two halves of the BCD deployment page are totally separate functions.
The top is for making external media, the bottom for repairing an unintentional corruption of the Vista/7/8 MBR IPL on your live system. Nothing you do in one half of the page has any effect on the other.
If you are trying to make a bootable flash drive, don't go clicking "Write MBR", It won't affect the flash drive, but it might do unexpected things to your live BCD.
EasyBCD Basics - EasyBCD - NeoSmart Technologies Wiki


New Member
Ok - not answered directly as i would have liked (understood - some of us need spelling out ..:smile: :smile: )

As Tumbling Toddler posted - and he is also using H drive - if we want to MBR it as it would be the first "DRIVE" when booting a system - is that the MBR it will "alter/fix/repair/install"

Surely that is a simple answer? MBR is first part of any (fixed?) drive! Right?
So if i select EasyBCD MBR util - will it only address the MBR of the selected BCD store device, e.g. "H" drive in our cases?

But from your answer- and i appreciate it ..you sound very much like it is a risky and unknown effect.....wow...that kills any possibility of using it if it has a mind of its own - not so?

Maybe we should use plain English - and worded for plain people?
Like Select your drive to affect/alter/repair the selected drives MBR! Drop down box or something!
Or tell us MBR to be altered is the one on the drive that has the selected BCD store on it!

Maybe just me but that makes it so much clearer?
Thanks anyway- got some bigger bugs to get help with in the meantime.

ps Terry, the new usb flash drives are SSD types and seen as fixed drives - just FYI - so WE WILL SELECT AND NEED THE MBR FUNCTION....
As my latest post shows i use these ..or am trying to - if OK i will never use a old flash drive (removable disk = 1 partition visible to M$ only - newer USB SSD type USB flash drives are seen as FIXED drives!!! Like Kingston Workspace Datatraveler 64GB)
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