Good morning, have been trying to install Windows 8.1 on my late 2012 iMac with no success. This is how it went, three times: after Bootcamp has downlowded microsoft support files on a usb key and created windows partition, it reboots the iMac. At reboot i receive on screen the message: disk inserted is not bootable (note that i have an original Windows 8.1, paid 129.99 ). At this point i restart pressing the option (alt) key and choose EFI boot to start windows installation which begins and continues to the point where i have to choose the partition for the installation. I choose the partition created by bootcamp but receive the message that "windows cannot install in that partition". That's it, no way to install windows 8.1. Any advice?