Help with deleting hard drive

I was using disc utility to delete my had drive on 2017 MacBook Pro. What a mess. I signed out of everything first but got confused when picking hardrive to delete. I’m sending this to Apple as a trade in and the computer was perfect. When I went to install OS it was installing Sierra. I had Catalina. I’m so crazy right now I can’t even upload a photo. Help.

After getting a circle w a slash in it and the folder w/ flashing ? I finally got an internal drive erased and Sierra installed. That was an experience.

This looks strange to me. You are looking at a disk image, the Type is listed as Disk Image External Physical Volume, but there is no external volume listed. Is that your OS installer? Where is it stored?

If you are prepping the system to turn over, you want to boot into Recovery Mode (hold ⌘-R during boot) and use disk utility to erase the disk then install the new OS from within Recovery Mode. That’s the only way to erase your boot drive.

Thanx for replying. I just recently erased the drive on an older computer that I was selling. I had never done it before but everything went smoothly; I just followed some instructions I found online. This newer computer that I was erasing, different story. I think I clicked onto the wrong thing on this page and deleted. That’s when the error symbols showed up. I was in recovery mode. The most I was offered was to install Sierra. I think I erased something important. It took many command R runs to accomplish that. This machine was my $1000 trade in that I may have messed up. Arrgg.

Don’t panic, @SteveH is pointing you in the right direction. Baring physical damage to the Mac I’ve always been able to reinstall the OS since Apple introduced internet installs.

Thanx for the reassurance @WayneG. The MacBook will be shipped from my friends house when the trade in kit arrives. I am now traveling. Other than the snafu that I created I know the machine is in excellent shape. I will just hope for the best return. Grateful.