Hello Calvin_Calvinstein,
Thanks for reaching out to us for support. We would love to help you. Just to make sure that we are on the same page, are you trying to get your Mac ready so that you can sell it? If so, please give the steps in the link below a try.
What to do before you sell, give away, or trade in your Mac
The reason we ask you to give the steps above a try is because they can potentially resolve your issue. Also, if you scroll to the bottom of the page, you'll also find guidance on how to reinstall the operating system on your Mac as well.
If you’re still experiencing the same problem after completing the steps above, please do not hesitate to reach back out to us so that we can continue troubleshooting with you.
Thanks for using the Apple Support Communities.
Cheers!