I keep getting this error when trying to upgrade Windows 8.1 on my 2013 Mac Pro. Here is a summary: 1. Apple Software Update did not show the Bootcamp 6 update, so I used the Bootcamp Assistant on OS X and it downloaded Bootcamp 6 onto a USB stick. I then used this in Windows to upgrade bootcamp. Looking at Programs and Features, I appear to have BC 6 installed. 2. I tried to use the normal download method twice and both times it came back with the same error 8007001F. I know there is another thread on this error, but I have managed to get past it (point 3) 3. I then downloaded the ISO and the USB DVD media tool to create a USB flash drive. I cannot boot from it, but when I run setup.exe I get as far as the "not enough space" error and cannot continue. 4. I have searched and followed the various suggestions, like using Trouble Shooting in Control Panel, running chkdsk /b, running Disk Clean up and so forth I am out of ideas. Has anybody encountered this on a Mac and managed to get past it? I see some people dual booting PCs with Linux have this issue, but their solutions do not seem viable on a Mac.