I have created a partition of MS-DOS FAT on my Mac, then created a Windows 7 Install Disk on my Flash Drive.

When I try to boot using the Install Disk via rEFIt. It just says no bootable disk found.

Why would OS X display a message like that if I used Bootcamp to create the Windows 7 Install Disk?

  • Have you selected the USB flash drive as boot-disk?
    – Michiel
    Sep 25, 2012 at 12:24
  • Yes I did. Could not work installing Windows 7 to my Mac through a USB. Just couldn't detect it. So I resorted to using a DVD installer with UDF format. I will try using the contents of the DVD though to create a USB installer and get back to this post should I find any success.
    – SleepNot
    Sep 26, 2012 at 3:15
  • It could be an issue with the USB drive. Switching drives solved a similar problem for me: apple.stackexchange.com/questions/75619/… Apr 12, 2013 at 1:34
  • Do you happen to have switched your SuperDrive for an SSD? I once had to reinstall the original drive because this model of MacBook would not boot from any other source when used for boot camp installation. Dec 26, 2015 at 12:14

3 Answers 3


i hade this problem a few times it's because os x somehow can't set the axtive flag which is needed by the bios/efi tho know at which disk thy should overgive the bootloader.

so you need to set the partition as active by hand via Terminal

  1. Go to finder/Spotlight, and launch Disk Utility
  2. Select the usb disk, and create a partition. Format it as MS-DOS FAT and select Options > MBR
  3. Go to the Terminal, and type the following

diskutil list

locate the name of your usb device. In my case it was rdisk2. Depending on your OS version it could differ.

diskutil unmountDisk /dev/rdisk2

Make the partition active and unmount the disk

sudo fdisk -e /dev/rdisk2 print f 1 write print exit diskutil unmountDisk /dev/rdisk2

have a look here for a colorful howto: http://tech.anoj.net/2013/01/fixing-unetbootin-on-mac-os-x-to-create.html?m=1


Are you sure the iso you started with was bootable ? some upgrade dvds are not bootable (tho most SHOULD be)

While rEFit rocks (all my macs have it) sometimes it just wont see a bootable usb, and sometimes it will see two bootable partitions on them ...

Try to boot with option key and see if osx bootloader recognizes it as bootable. If it also doesn't recognize it, go back to OSX and re-create the boot drive preferably on a different (brand) pendrive.


I had the same problem! I found that if any other peripherals that were connected like hard drives and any other storage devices need to be disconnected except for the drive that has the OS!

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