\Steam\steamapps\common\Halo The Master Chief Collection\MCC\Content\Paks\MCC-WindowsNoEditor.pak
(Create a backup of this file before changing anything)
Open the MCC-WIndowsNoEditor.pak file in HxD.
In HxD, Press Ctrl+G
Enter 1E302110 as HEX and when clicking the "OK" option you should have your cursor selected on a line starting with 00
Change the 00 to 27,
Press Ctrl+G again, but this time search 1E2F52D0 as HEX
Do the same thing, change the first 00 that you land on to 27,
Load up mcc
Boom, The create option SHOULD be on your user interface now.