Why do I receive a “No MBR Magic” error when trying to install Windows 7 via USB?

David Calder-Flynn January 3, 2013

I am installing (well trying to) windows 7 on a new computer with no software. I have gone through all the steps found here:

How can I install Windows 7 via an ISO file?

I have set the BIOS to USB first and it seems to run okay but then the following text comes up:

No MBR magic.
Warning: treating disk as raw.

It doesn’t do anything else. Can someone please tell me if i am doing something wrong or if it just takes quite a while to install.

  1. Alan Wade
    January 3, 2013 at 10:16 am

    This link explains about the "Magic Number" : http://mbrwizard.com/thembr.php

  2. ha14
    January 3, 2013 at 8:40 am

    something went wrong during the creation of the usb key?

    The MBR Explained: Magic Number
    Located in the final two bytes of the MBR (511-512), this section must contain the hex value AA55, which officially classifies this as a valid MBR. An invalid magic number indicates a corrupt or missing MBR, therefore these bytes are critical to booting or using the disk.

    How to rebuild MBR with magic partition manager?

    How To Create Bootable Windows 7 USB To Install Windows 7 From USB Flash Drive (Using Windows 7 DVD/USB Tool)