Windows 10 Anniversary Update fails to install on Mid-2012 non-retina MBP.

I'm trying to update my Boot Camp installation to the Windows 10 Anniversary Update and it keeps failing at 71% when setting up Windows. It suddenly reboots and reverts back to the previous version of Windows 10 1511. No error messages are given that show why the installation failed after booting back to the old version.

I tried it through Windows Update and the Windows 10 upgrade assistant and both don't work. The Media Creation Tool fails with the error 0x8007042B - 0x3000D with the message "The installation failed in the FIRST_BOOT phase with an error during the MIGRATE_DATA operation".

Anyone have any ideas? I'd prefer not to do a clean install if I don't have to.