I have an El Capitan, can I create a bootable USB of Windows 7? I also have a Windows 7 ISO. I need to use a USB since I will be reformatting a netbook without DVD/CD-ROM drive.
As @hirnwunde has pointed in the comments, the article from Indiana University works!
- From the Finder, open the Applications folder, and then Utilities.
- Open the Boot Camp Assistant, and then click Continue. The next screen should give you a list of options.
- UITS recommends making the USB drive installer first. You don't need to install Windows or download the support software at this time, as it will be easier to do both later. To proceed: a. Verify that the USB drive you will be writing to is plugged in. b. Uncheck the Install Windows 7 or later version and Download the latest Windows support software from Apple options. c. Check Create a Windows 7 or later install disk and click Continue.
- Your USB drive should be listed in the "Destination disk" area. Use choose to browse to your .iso file; after selecting it, click Continue.
- If prompted, confirm your action and/or provide an administrator's password. The process of writing the .iso file to the USB drive can take 20 minutes or longer.
In latest El Capitan there is no option to create USB disk in Boot Camp Assistance, but you can create USB drive in Terminal.app
If you're one of the people who no longer have the option to create a thumbdrive in Boot Camp Assistance, here's how to get around it.
- In Finder go to Applications/Utilities and copy Boot Camp Assistance
- Navigate to ~/Applications and paste Boot Camp Assistance there
- Using your favorite text editor open
~/Applications/Boot Camp Assistant.app/Contents/Info.plist
Find the area that looks like this:
<key>ExternalInstallOnlyModels</key> <array> <string>MacBook8,1</string> <string>MacBook9,1</string> <string>MacBookAir7,1</string> </array>
Add your model to the list (you can find your "Model Identifier" in About This Mac -> System Report). For me (MacBook Pro, Retina, 15-inch, Mid 2015), that means it now looks like:
<key>ExternalInstallOnlyModels</key> <array> <string>MacBook8,1</string> <string>MacBook9,1</string> <string>MacBookAir7,1</string> <string>MacBookPro11,4</string> </array>
Check if your model is listed under PreUSBBootSupportedModels. If so, remove it.
Now start Boot Camp Assistance from your Applications directory and you'll get the option to burn to USB.