I found a way to activate your current install of Windows 10 without formatting.
The 0xc004f050 error is caused when you do a clean wipe of your OS before upgrading to Windows 10. I was told by Microsoft that there are only 2 ways to fix this error;
1. Reinstall your old OS (7, 8, 8.1) and wait for the Windows 10 app to downloaded Windows 10 to your computer, then upgrade using the app.
2. Buy a Windows 10 license for $119 -199 (depending on Home or Pro)
I did neither of these. Well, sort of. I didn't want to lose my current install of Windows 10, so I installed Windows 7 (my old OS) on to a different drive. Once I loaded into and activated Windows 7, I downloaded the Windows 10 ISO (https://www.microsoft.com/en-us/software-download/windows10) to a USB stick. Without restarting, I launched the Windows 10 setup on the USB. I installed Windows 10 as an upgrade and it never prompted me for a key. When it was done installing, it automatically activated.
At this point it is important to note that the 'Get Windows 10 app' did not appear before I launched Windows 10 setup.
Now this is the important part; once Windows 10 was activated on my computer, I swapped back to my original drive(the drive with the non-activated copy of windows)and when logged in, it automatically activated. The best part, not a single file or application is missing.