Windows 8.1 installation errors via Bootcamp.

Hello,

I'm trying to install a full, genuine version of Windows 8.1 onto my Macbook Pro (13-inch, Early 2011) via Bootcamp 5.1.4, on OS X Yosemite 10.10.3.
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2.3 GHz Intel Core i5
4 GB RAM
Intel HD Graphics 3000 384 MB
500 GB SATA Disk

420.64 GB free of 499.25 GB
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I'm using an external optical drive and the Windows 8.1, 64 bit installation disk. I have downloaded the "latest Windows support software from Apple" onto a 8GB USB. I partition my hard drive to have 70GB of Windows and the rest OS X. After it has finished partitioning the disk, my Macbook reboots and about five seconds later, a grey screen with a flashing underscore appears in the top left of the screen. I'm not able to do anything at that point.

I force shut down, and turn my Macbook back on while holding 'option' to access the boot menu. When the boot menu appears there're four options (when the external optical drive is plugged in), "Macintosh HD, recovery drive, Windows, EFI Boot". I tried selecting "Windows" but it just returns to the grey screen with the flashing underscore. I left the grey screen on for 30+ minutes to see if anything will happen, but nothing did.

I have tried restoring the partition and re-partioning it and trying again, but the same grey screen comes up. I have tried unplugging the external optical drive when the Macbook reboots but it just sates, "No bootable device -- insert boot disk and press any key", I then plug the external optical drive back in and press any key, but it just stays on that screen.

I made an ISO file of my Windows 8.1, but the first thing you see when you open bootcamp is a warning stating, "You need an optical drive to install Windows. Connect an optical drive to your computer. You can't install Windows with a remote optical drive."

Any help at all will be greatly appreciated.

Thanks,
Joel.

Welcome to the Mac Forums.

Why are you installing Windows 8.1 from an external optical drive? Your MBP has a built in optical drive which means Boot Camp will only install from there. That's the reason you're seeing a grey screen with a flashing cursor. Macs without an optical drive allow Windows to be installed from an external optical drive or USB flash drive, but not your Mac since it has an optical drive.

And if you have removed the optical drive to make room for a second hard drive, remove it, re-install the optical drive and go from there. If the internal optical drive has failed you are in the market for a new one if you wish to use BootCamp.