Changed User Account from ADMIN to STANDARD and don't know ROOT pass

[Linuxmintcinnamon]

Hey,

I'm somewhat new to Linux, and Cinnamon 19 Beta, and have been locked out of all administrative controls.
I accidentally switched my User Account from ADMIN to STANDARD when configuring my preferences.
I am unable to access User Controls, or anything else for that matter, that involves elevated privelleges.
Everytime I try to do so I am prompted to enter the password for the Root account, which I did not set.
Please let me know what I should do as I'm unclear of what steps to take and would prefer to not toy with it for hours..
still quite new to Linux in general. Here's more information if necessary, thanks for your help!

OS: Linux Mint Cinnamon 19 Beta x64
PC: Well above the minimum requirements for install (no issues there)
SPECIAL NOTES:
1. Originally installed through OEM option, configured by myself, and used the same temporary password for my current User Account
2. The system is encrypted, of which I obviously know the password to.
3. I've tried any default password(s) I could think off including: ____ (blank), admin, cusadmin, 12345, root, toors
4. The current User Account is the original, and only, User Account on the system so not an option to log into another known Admin Account
5. I made a RESTORE POINT just before I configured the preferences, but haven't been able to access it without elevated priveledges
6. I still have the bootable USB used to install the system

Thanks again guys, let me know if you need any other information! Have a great weekend

[JerryF]

3. I've tried any default password(s) I could think off including: ____ (blank), admin, cusadmin, 12345, root, toors

Did you try using your password when it asked for elevated privileges?

[Linuxmintcinnamon]

Yes I have unfortunately Any other suggestions? Possible to go through the terminal interface and do it that way?

[JerryF]

I'm not adept at terminal commands.

[gm10]

Reboot, access the GRUB2 menu by holding down shift during boot, select advanced options, boot into recovery mode, select root shell, type

Code: Select all

mount -o rw,remount /
adduser YOURUSERNAME sudo
adduser YOURUSERNAME adm
reboot

Obviously replace YOURUSERNAME with the actual name of the user that should become admin again.