Hi Pharotek,
I had the same issue, trying to install Windows 7 on my new iMac yesterday and this morning. I couldn't ever get it to work in any configuration of usb port plugging 😟 but I read a lot of those suggestions too. Ultimately, I borrowed an external dvd drive and burned the Windows 7 iso to a dvd. Booting from the external dvd did the trick. To summarize, so hopefully I help others with this terribly-frustrating problem:
- Use the Bootcamp Assistant to remove any half-finished windows partition (that should be checking the last checkbox only, to "remove").
- Plug in an external dvd drive with a Windows 7 install disk. (Use the Disk Utility to burn the ISO to the DVD if needed.)
- Plug in a USB thumb drive, which we will use to hold the Apple support files.
Because order seems to matter, on my iMac with 4 usb ports at the back, facing the back of the iMac from right to left I had: external DVD drive, thumb drive, blank, apple keyboard w/ non-apple mouse plugged into keyboard.
- Use Bootcamp Assistant:
- uncheck option one (we don't need to copy the iso to the thumb drive, since we're using dvd)
- check option two (we do want to copy the support files to the thumb drive)
- check option three (we do want to install Windows! 🙂)
- During the install process, if you've been booting from USB thumb drive, you'll likely get a message about making the thumb not bootable. Yes, we want to make the USB thumb drive not bootable now, as we are booting from the DVD and just using the thumb for support files.
- Now the installation should work. Select the bootcamp partition, choose advanced, choose to format the BOOTCAMP partition as usual.
- Dance around the office (optional.)
I believe the core issue is a unhappy melding of USB 3.0 issues and having a bootable USB thumb drive be the source of installation.
My external DVD drive was an Apple USB SuperDrive.
