10 Replies Latest reply: Dec 13, 2011 10:08 AM by Mihai S.
Mihai S. Level 1 Level 1

If you want to install Windows from a USB drive, you'll need the Boot Camp Assistant (version 4.0.1) and a MacBook Air. I don't know why it won't let you do it on other Macs and MacBooks (the option still shows up, only it's greyed out) - if you made it work on anything other than a MacBook Air, let me know how you did it. So, besides that, you also need an empty USB drive and a genuine Windows ISO file.





However, if in your case the Windows USB creation option is greyed out, this is what you can do:


  • You create the Windows installation USB, using one of these two ways (I used the first one):
    1. http://technet.microsoft.com/en-us/magazine/dd535816.aspx
    2. http://www.microsoftstore.com/store/msstore/html/pbPage.Help_Win7_usbdvd_dwnTool
  • You create the Windows partition with BCA.
  • In System Settings, you choose the newly created BOOTCAMP partition as the startup disk and restart your Mac.
  • Have your Windows USB inserted before your Mac restarts.
  • As soon as your Mac boots from the BOOTCAMP partition, it should start loading Windows Setup from the USB drive.


I have an early 2009 MacBook and these steps worked for me. It's a workaround... but it works. Let me know if it worked for you.



* If none of this works for you, there is another workaround, using 3rd party software (rEFIt). However, I don't recommend using it, unless you know what you're doing.

* Disclaimer - This info comes as is and I do not guarantee that it will work for you. Nor do I guarantee that it will not cause any malfunction to occur on your Mac computer.

iMac, MacBook, MacBook Air/ Pro, Mac OS X (10.7.2)
  • lahotin Level 1 Level 1

    Can you just tell me how should I select to boot form my bootcamp partition. Bootcamp Assistant does'nt allow you to make it into a NTFS Paritition. I can't select to boot from my bootcamp partition.

  • Jaygyver Level 3 Level 3

    I would imagine when yo get the USB Windows installer done you would either have Boot Camp assistant startup from it or you would just insert the USB stick just like you woud insert the Windows Disk to format the partition and then install when it's asked for.

  • Mihai S. Level 1 Level 1

    you restart your mac and as soon as it boots up (usually you hear the dvd making a noise, or the gong sound), you hold down the Alt key until you see a screen that shows you all the partitions/drives you can boot from. you select the boot camp one, while the windows usb installation disk is inserted and it should boot up from the usb. it worked for me, but I can't guarantee it will work for you too... depending on your model. mine is an early-2009 macbook.

  • Mihai S. Level 1 Level 1

    the way I did it was by booting up into the boot camp partition, while the usb was inserted, even if there was nothing installed on the boot camp partition. this way it made it boot up into a DOS-like environment, which, luckily, recognized the windows usb, booted from it, and started the installation.

  • Mihai S. Level 1 Level 1

    boot camp formats the 'bootcamp' partition as fat32, as far as I know. It's up to you to format as ntfs from the windows installation wizard.

  • lahotin Level 1 Level 1

    I have a early iMac 2011. I followed ur instructions but i didnt work for me. Screen just shows Macintosh HD and Recovery HD.

  • lahotin Level 1 Level 1

    Yeah. If the Installer doesn't load up, how can i format in the NTFS format. Ther has to some way. I have tried rEFIT also.

  • Mihai S. Level 1 Level 1

    if the usb installation doesn't work, then use a windows dvd. that should definitely work.

  • lahotin Level 1 Level 1

    I would surely try do it but I can't my superdrive is broken. It wont boot form a external dvd that the problem.

  • Mihai S. Level 1 Level 1

    you say you tried rEFIt? what happened when you tried it?