SupportAssist and USMT.mig file

HI, In another post I stated I was having issues with my XPS 8930 upload speed being almost 0. I eventually found that it was an issue with the "Killer Ethernet device" and the latest "Dell update" for the device caused the slow upload speed. I did manage to correct that issue. Figuring that it was related to an "Update" I attempted to go back to a "restore point" before the last update. That did not go well, and the computer froze and had trouble booting. So I went to Dell's SupportAssist to try and return my computer to "normal". In doing a reset/repair, the program asked me if I wanted to save my data files -- I said yes, and a 12.9GB file  named "Do_Not_Delete"  was saved on an external drive. 

SupportAssist did it's work and "reset" my computer to what I would describe is a fresh Windows-10  install -- all my data and installed programs were lost. I wasn't too worried since it appeared that this information was in the saved "Do_Not_Delete" file. However, SupportAssist seemed to ignore that file.  So I was left with a bare Windows-10 computer. I did some digging and found out that the "Do_Not_Delete" file had various folders named "USMT" and also a file named "USMT.mig" which seemed to have all my lost files in a compressed form. THE PROBLEM IS THAT THERE SEEMS TO BE NO WAY TO UNCOMPRESS THIS FILE AND RECOVER MY DATA.  Can anyone tell me how to extract my files from this compressed form.