WinRE Missing Administrator Accounts

I just purchased a Dell OptiPlex 7020 from DellRefurbished and got it upgraded to Windows 10, but have been running into an issue. This all started, due to my own ignorance. Anyways, I wanted to create a new backup image after I got all of the bloatware and unnecessary apps off of the computer and a few essentials installed. I plan on gifting this computer to my father. Anyways, after getting everything the way I wanted it, I decided to delete a partition (named PS Image) Dell had created that (my best guess) was a Factory Reset Image of the PC, which I deemed useless, since he is on Windows 10 and if he has to restore, that means going back to Windows 7 or 8 (unsure which was stock); upgrading Windows 10 and tweaking and installing everything all over again. I ended up deleting a partition and created a new image, using the Windows 7 Backup Image creation program. Anyways, I went to test this image and found that it said I had to login to an Admin Account, but no admin accounts show in the list; in fact, no accounts show in this list. Is this something to do with upgrading to Windows 10? I have checked and the account is active and I am able to do anything in Windows that requires Admin rights. I did keep the “WinRE Tools” partition that came on the drive. Do I need to re-create this? I want to keep it simple, so he can just navigate through WinRE and restore, if needed. Any ideas?