If you have a MacBook Retina or a (newer) MacBook air and you are stuck at the installation of Windows when you are trying to install Windows on a Bootcamp partition, try this:
1. Put Windows ISO file on your computer, doesn't matter where (for example Desktop). Have USB drive ready, insert into USB port.
2. Open Boot Camp Assistant, check all 3 boxes -- make boot disk, download software and partition disk. Go through screens until it ends at screen where you can only click quit (You will not make it automatically to the Windows 7 install blue screen just yet.) If you were to reboot your computer (holding down 'alt/option' key) you would get back to blue Windows install screen with no cursor.
3. Reopen Boot Camp Assistant and this time CHECK THE THIRD BOX ONLY, the one to partition your drive. Be sure to leave the first two unchecked. Choose your partition size (I did 80gb for the bootcamp disk). You'll notice that when Boot Camp is done partitioning the disk it will automatically quit Boot Camp and reboot your computer, which it didn't do the first time.
4. As computer is automatically rebooting, hold down alt/option key until you see screen where you can choose to boot up with mac HD or your windows USB. Select 'windows' drive by clicking on it or arrow just below.
5. This time when you go through initializing black screen and then first blue Windows 7 screen, you should have a nice big fat white cursor that works.
(found at Apple Discussion forum, post by jcrenard