Update Feb 6, 2013: See Lior’s comment/fix to Bootcamp Assistant not giving the option to make your USB drive into a Windows installation bootable drive.
Here’s my solution to the ”Installer disc could not be found” problem when installing Windows on a Macbook Pro Retina with Bootcamp using Bootcamp Assistant. At the Install step, after sizing partitions for the Macintosh HD drive, Bootcamp Assistant will return an error :

Bootcamp Assistant 4 is a step-by-step program on Mac’s (available in “Other” programs group, same group where you find Disk Utility, visible below) that will guide you through setup of dual boot Windows and Mac OS X on your Macbook/iMac/Mac Pro. Bootcamp Assistant can create a bootable Windows installer USB key from your Windows 7 ISO image file (download official Windows 7 ISO images) or use your Windows install DVD if you have bought one, but Bootcamp Assistant sometimes can’t recognize the USB key as being a bootable “Installer disc” when the Partitioning step of Bootcamp Assistant is reached.
The solution: use Disk Utility to partition Mountain Lion’s hard disk, then restart holding alt/Option key and choosing the Windows USB key install image as the drive to boot from.
Finding Disk Utility on Mac OS X Mountain Lion:
Start Launchpad, click on Other and find Disk Utility.



Launch Disk Utility. You’ll see something similar

Select the top most drive, which should be your 251 GB or 502 GB APPLE SSD.
On the right you’ll see 5 tab buttons: First Aid | Erase | Partition | RAID | Restore.
Choose Partition. Then click the + button below left of the rectangle. This adds another partition to the rectangle, separating the top and bottom with a bar. Drag this bar up and down to resize your OS X Mountain Lion partition (space on the drive dedicated to Mac) and the BOOTCAMP partition that you will create to hold Microsoft Windows. I went with about 60GB.
Change the Name to BOOTCAMP or something that helps you remember this is your Windows partition.
Change the Format to MS-DOS (FAT). This will be reformatted during Windows installation to NTFS. Click Apply to save the changes and then reboot your Mac and we’ll begin Windows installation.

During reboot, you’ll hear the startup “Chime”. Press and hold the alt/Option key and you’ll be presented with drives to boot from. Use the arrow keys and return button to select the Windows yellow USB key drive containing your Windows 7 installation files. This will begin the Windows install.

First screen where you’ll need to make selections is the drive selection of where to install Windows 7. Select the BOOTCAMP partition you created in Disk Utility.

Click Drive options (advanced). This will reveal the Format option, which you’ll need to use in order to reformat the partition for use by Windows 7 (formatting the partition to NTFS).

Follow the rest of the Windows installation steps and stay at your Mac during the process. Windows will need to reboot several times during the installation process and you’ll need to be ready to press/hold the alt/Option key during the Mac boot-up chime so you can select the BOOTCAMP partition to boot up into to continue the installation process.
Once the install is complete and you’ve booted into Windows 7, don’t forget to install WindowsSupport files that were put onto your Windows 7 installation USB key.
These support files adjust the resolution and keyboard/trackpad for best usability.
Enjoy your Bootcamped Macbook Pro Retina with OS X Mountain Lion and Windows 7!
Lior’s solution to no-bootup option for your USB drive Windows installation disk in Bootcamp Assistant (thanks Lior!):
If you have only 2 options in the boot camp assistant, or if bootcamp doesn’t recognize the windows installer disk when its on a bootable usb, it’s because bootcamp doesn’t recognize your macbook as a model that should install windows from a USB, its actually quite easy to fix, just follow these simple steps:
1. go to Applications>Utilities> right click on boot camp and click Show Package Conents, you’ll find a folder inside called Contents (If i remember correctly, not on my Macbook atm). Inside that folder exists a file called info.plist.
2. Right click on the folder containing the file > get info > change permissions so any user can read & write. Do the same for the file itself (right click > get info…).
3. Right click on info.plist and choose Open with > Text Edit.
4. at the end of the document theres a list of strings that contain different versions of Mac computers, the list is titled something like: “USB boot Versions”, add your Mac’s version to the string list ( MB40 ) if your version is Macbook 4,1 (you can see this by clicking on the System information App in the Utilities folder).
5. save the file and change back the permissions on the file and folder.Now open boot camp and you should see the option to create a Windows 7 installler on a USB, and also bootcamp will look for a windows installation on any USB’s after you partition the hard drive.
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36 comments
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November 2, 2012 at 6:58 am
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August 10, 2012 at 12:27 pm
User
Wireless drivers don’t seem to work for me with either Windows 7 or Windows 8 with the new Retina MBP. Any ideas? I’m using Mountain Lion…
August 25, 2012 at 3:21 pm
Rui
A little question please, How do you create the Windows 7 USB Key ? what do you mean by that ? An usb drive ? how does the bootcamp assistant create a bootable Windows 7 Bootable USB stick ?
August 26, 2012 at 3:51 pm
Ben Lam
Rui, I’ve added a link for Windows 7 ISO install images to the article. You need a blank USB key (4GB was sufficient for me) for Bootcamp Assistant to load on a bootable image of Windows 7. Thanks for the questions.
August 27, 2012 at 10:32 am
Rui
Thanks alot for you answer Ben
The problem is i have an older macbook pro (late 2007 / 2008) and i’m afraid it won’t boot from usb sticks. Not even with rEFit installed. Or is there a kind of trick to make the USB boot in older macbook pros ?
Thanks again in advance,
Greetings
August 27, 2012 at 1:16 pm
Ben Lam
Hi Rui,
I also have a 2007 MacBook Pro and I can boot from USB sticks and drives without any problem.
When you press & hold the alt/option key after hearing the boot-up “chime”, your Mac doesn’t show on screen the various drives from which you can boot? (That you select using arrow keys and enter button)
August 27, 2012 at 3:50 pm
Rui
Hi Ben, It does show, But when i click on the windows USB stick, It gives me a list of errors (lettres are in yellow) and then i have to reboot.. Is there a special way to do it ? I have the ISO, do i only open the ISO on my mac, and copy the content to the USB drive ? (wich is formated in FAT file system btw)
Thanks again for your answers and help, very much appreciated!
August 28, 2012 at 1:32 pm
Ben Lam
Hi Rui,
To make the bootable USB key, you should have Boot Camp Assistant make it for you.
When you start Boot Camp Assistant (assuming version 4), there will be a screen with three checkbox options, the top being “Create a Windows 7 install disk”.
Having that checked (only) and running Boot Camp Assistant (which will ask you for the location of a Windows 7 ISO image saved on your computer) will create you a proper bootable Windows 7 USB key.
Let me know how that works.
August 28, 2012 at 2:11 pm
Rui
Hey Ben, It doesnt work with me, Because I only have 2 options. Wich are the Download windows support files, and install windows :/ So i guess my hardware is not compatible with that unfortunatly :/ (my bootcamp version is version 5..)
Thanks again alot Ben,
Best Regards
September 4, 2012 at 3:49 pm
Martin
FYI, I just did this and worked great - I used the Windows DVD rather than the USB but it shows up in the same way when you reboot holding down the alt/option key.
thanks!
September 24, 2012 at 2:04 pm
Dmitry
I have disk problem after instalation. the W7 takes about 37 gb spase on the disk.
what i coud be. it’s clear windowa without any program i shouldn’t takes so mach spase
November 6, 2012 at 5:59 am
Lior
If you have only 2 options in the boot camp assistant, or if bootcamp doesn’t recognize the windows installer disk when its on a bootable usb, it’s because bootcamp doesn’t recognize your macbook as a model that should install windows from a USB, its actually quite easy to fix, just follow these simple steps:
1. go to Applications>Utilities> right click on boot camp and click Show Package Conents, you’ll find a folder inside called Contents (If i remember correctly, not on my Macbook atm). Inside that folder exists a file called info.plist.
2. Right click on the folder containing the file > get info > change permissions so any user can read & write. Do the same for the file itself (right click > get info…).
3. Right click on info.plist and choose Open with > Text Edit.
4. at the end of the document theres a list of strings that contain different versions of Mac computers, the list is titled something like: “USB boot Versions”, add your Mac’s version to the string list ( MB40 ) if your version is Macbook 4,1 (you can see this by clicking on the System information App in the Utilities folder).
5. save the file and change back the permissions on the file and folder.
Now open boot camp and you should see the option to create a Windows 7 installler on a USB, and also bootcamp will look for a windows installation on any USB’s after you partition the hard drive.
That should get you past the bootcamp assistant phase, assuming your usb is indeed bootable, your mac should partition the disk and boot into the USB and start the installation (for some reason mine doesn’t recognize the USB as bootable but thats another issue)
November 21, 2012 at 10:16 pm
thomasloh
How come when i reboot i dont see the selection of Windows i only see Mac and Recovery
November 21, 2012 at 10:17 pm
thomasloh
How do you update your bootcamp to bootcamp 4?
December 1, 2012 at 11:27 pm
akherousia
Lior, thanks for your help.
I was struggling with this for 2 days.
December 7, 2012 at 5:42 pm
Raeafa
I already have created USB key drive containing your Windows 7 installation files using bootcamp and already created a partition, but when I restart the system and hold ALT/Option it only appears the Macintosh HD and the Recovery 10.8. The yellow flash drive icon “Windows” dosent appear at all!!
What could it be???
Thanks
December 28, 2012 at 11:06 pm
Mike
I’m in the same boat as thomasloh and Raeafa. I’ve created the Win 7 USB installer but it does not show up in the list of bootable volumes.
January 15, 2013 at 2:22 am
Grant
Im also in the same boat, that drive does not show when hitting option on startup, and my computer is not reading the windows installer DVD, its just ejects automatically after it spins for a few seconds. Disc is not damaged, and i cleaned the superdrive before attempting. Have the iso file, but still not working. Help would be appreciated!
Thanks
January 23, 2013 at 1:06 am
Dima
Pomogite pojalusta… Vo vremya ustanovki windows 7, posle formatirovat razdela najimayu DALEE daet oshibku: “Программе установки не удалось создать новый или найти существующий системный раздел. “
January 27, 2013 at 10:56 am
Sitaram
I tried all the steps mentioned, when I trying to install windows, it doesn’t provide the option of choosing which partition? Thanks for your help.
January 27, 2013 at 11:30 pm
nck
Thanks, Lior!
If you’re adding your hardware string to the Boot Camp Info.plist, make sure your model comes BEFORE the existing later model or it will not work:
MBP51
<string<MBP90
January 29, 2013 at 5:35 pm
Paul
Has anyone got this to work. My computer doesn’t recognize the flash drive I have when I reboot holding the alt key. I did all steps required and still no luck.
February 6, 2013 at 4:44 am
Mort
Same as above. Tried both USB with updated info file and a dvd as well. I read somewhere that mountain lion does not have the drivers to boot Windows formatted startup disks. Could that be the problem? In that case I would like my money back until it does..
February 6, 2013 at 6:39 pm
Matt
The USB stick with the windows 7 iso isn’t displaying when i hold the option key? What can I do?
February 6, 2013 at 7:13 pm
Ben Lam
Matt: the USB stick needs be a Windows 7 *boot* drive, not the ISO of Windows 7.
The Win7 ISO is used to make the USB stick a boot drive with the help of Bootcamp Assistant while using Mountain Lion.
February 6, 2013 at 7:59 pm
Matt
Thanks for the response Ben, I’ve looked in and out of bootcamp assistant and haven’t anything in regards of creating a bootable USB stick.
I have access to a Windows computer that I can use a program to create a bootable USB for Win7, would this work?
I would use the DVD but the installer gets stuck on “Windows expanding files 0%).
Any help is appreciated.
February 7, 2013 at 3:32 am
Ben Lam
Hi Matt,
If you have a Windows PC, you can use that machine to create the bootable USB key with Win7 and use that during the Bootcamp Assistant setup.
Also, have a look at Lior’s comment above regarding whether your particular Mac is one listed as “bootable by USB key”. (You can fix it if not).
February 7, 2013 at 10:36 am
Matt
Ben, I do have another PC and I used that tool to create a bootable Win7 USB stick and it still didn’t see it when I rebooted.
I also have a brand new iMac, I used the create a bootable Win7 USB stick via bootcamp and my early 08 MacBook still didn’t see the USB drive upon start up.
I even went to the extent of installing refit so I could get a better boot screen and it still doesn’t see it.
I’m at a loss here and I need Windows on this thing for school work. I don’t want to use parallels.
Is there anyway that I can use an external hard drive? Or any other options??
Thanks!
February 7, 2013 at 10:47 am
Ben Lam
Hi Matt,
If you have an external hard drive, I would try that, just to eliminate the possibility something is wrong with your USB key.
You could get extreme and pull out the hard drive from your 08 Macbook, connect it to your PC (either via a usb drive caddy or directly if possible) use partition magic or similar to repartition it, adding an NTFS partition, installing Windows 7 onto that partition, then reconnecting it to your Macbook and seeing if you can hold Option and see that bootable partition.
With my old 07 Macbook Pro, I used to have two identical disk drives that I could swap in and out while trying crazier/riskier stuff like this.
February 13, 2013 at 7:48 am
Victor
So I did everything exactly and it all was working till i get to the formatting part. I format the partition but then it gives me an error saying
“windows cannot be installed to this disk. The Selected disk has an MBR partition table. On EFI system, Windows can only be installed on GPT disks
Windows cannot be installed to this disk. This computer’s hardware may not support booting to this disk. Ensure that the disk’d controller is enabled in the computers BIOS menu”
I’m at a loss here.
February 13, 2013 at 12:20 pm
Ben Lam
Victor,
Take a look at the screenshots in the article, the second Disk Utility one, which is titled APPLE SSD etc.
Look at the bottom right hand corner where it says Partition Map Scheme: GUID Partition Table. This is GPT. When you’re in Disk Utility on your Mac, does it say the same or are you on Master Boot Record (MBR)?
If you’re in MBR, I think you’re stuck unless you want to reformat your entire disk as GPT, create two partitions, one for OSX and another for Windows, reinstall OSX and go through the Bootcamp process again in prep for installing Windows on Bootcamp.
GPT formatted disks allow disks to be above 2TB in size. MBRs are old-school which can only support disk sizes below 2TB. More info: http://en.wikipedia.org/wiki/GUID_Partition_Table
February 14, 2013 at 7:28 am
Victor
Thanks a lot for the reply Ben,
Yeah mine says all the exact same things as it does in the screenshot up above “Partition Map Scheme : GUID Partition Table” and everything else.
When I go back to OSX after failing to continue installation after formatting the partition, I check the partition and it is in “Windows NT File System (NTFS)”. I’ve looked around the internet and I cant seem to find an answer. I’ve retried all the steps 5 times with the same outcome. The only thing that’s different is when I go to format the partition, under “Type” mine says “Primary” not “System” like it does in the screen shot above 9not sure if that’s anything, just saying).
Don’t know if it matters but I’m on a 27-inch, Mid 2010 “iMac11,3″ Intel Core i7 1TB running Mountain Lion, and I’m booting Windows 8 off a USB stick.
Again thanks for replying.
February 21, 2013 at 9:16 am
Bassel
im as same as vector
February 23, 2013 at 6:15 am
Bassel
victor*
i have the very same problem of victor
except im on a macbook pro 17″ early 2011
i have a 750gb hdd drive and a 256gb samsung ssd
February 24, 2013 at 7:13 am
Alex
I’ve got mbp80 (macbook pro 13 early 2011) and this doesn’t work for me.
It seems that the problem is not so easy to solve. Lior’s method does work for the first step: in bootcamp I now can create bootable usb stick. But when I run ‘Install Windows 7′, mac reboots and then doesn’t recognize usb as bootable. Lior’s usb didn’t work either, so as couple of people’s sticks as seen in comments.
On russian site http://goo.gl/F7puL described the same as Lior’s way to install win7 from usb, but in comments TS says that it turns out that you can boot only on mbp 2012 and later, mba 2010 and later and so on. In comments somebody said that refit helped with macbook bro 7,1, but for me it don’t work too.
Any ideas?
March 25, 2013 at 8:59 pm
Serian
With Bootcamp 5.x the steps to get the 3 options available is slightly different than what is listed.
In the DARequiredROMVersions array, add a string at the top that contains your Boot Rom Version that can be found in System Information.
This is mine:
MBP81.0047.B27
Next go to the PreUSBBootSupportedModels array and add a string at the top that has your Model Identifier (also found in system info).
Mind is:
MacBookPro8,1
After adding these two strings and saving Bootcamp no longer told me that I needed an optical drive to install Windows.