I think I made a mistake changing the lightdm theme and now my system won't load, it stays on the zorin loading screen, when I press escape it shows me this
I think I should be able to enter a console where I can log in and start my system but I don't know how.
I have tried CTRL+Alt+1-6
That line at the end says:
A start job is running for Hold until boot process finishes up (<time running> / no limit)
time running has been about half an hour already
Hi,
Sorry to hear of your woes. Keep pressing the left Shift key during boot which should give you a menu option to choose Advanced boot of Zorin (equivalent of safe mode in that other OS). Use the troubleshooting option that should give you a DOS type window and select networking (you should have a wired connection preferably to your router) and select Terminal with Root privileges - once there you can then login to your system and make changes. If you are running core, try changing from lightdm to GDM (Gnome Desktop Manager).
If booting with Legacy boot, hold the Left Shift Key down starting at powering on the computer.
If using EFI Boot, you will need to stab the esc or tab key with your finger like it is an alien life form looking to invade the Earth and only Facebook Pokes can stop it.
What did you change?
Was going to suggest getting to the advanced start terminal and purging / reinstalling lightdm - I'll wait! haha
+1 @Aravisian on the description! 
I like the ol' button-mash like you're playing Street Fighter - with turbo on 
I have also used "Mortal Kombat" testing your might.
I believe that the O.P. is trying out LightDM as per a suggestion in another thread where he asked about SDDM.
Thanks, I done that, just I do not go to networking option, went to dpkg, there I just ran: dpkg-reconfigure gdm3 and reboot
Yes, that's me, I have to double check but believe that the problem was changing the lightdm theme I just write something wrong and stupidly restart without testing, then when my system starts it was unable of start lightdm service because it does not find that theme...
About my other post I do like lightdm and going to try keep it I just have to get through all the process to learn how to customized, the principal reason because I left "that other OS", like @swarfendor437 said, is the opportunity of having a system of mine, technically as much as visually
Install
sudo apt install lightdm-gtk-greeter-settings
Start with the GUI settings app. It has most things that you can change included there.
Going deeper, you can change the top panel (that can be moved to the bottom too) appearance using a custom .css sheet.
Somewhere, I have a saved file that lists all the different config settings for LightDM. I can try finding that...
