Format Mac mini without upgrading

[nampramos]

Hi,

Hoping to get some clarity on the process of formatting my Mac mini 2018 that’s running Catalina without having it self upgrade to Big Sur.
The new buyer wants it on Catalina.
So I’d like to safely erase all my data but still keep it on Catalina.

Could someone be so kind to give me the quick steps so I don’t mess up and it upgrades?

Thanks a lot!

 

[duanepatrick]

Found this similar thread: https://forums.macrumors.com/thread...without-reinstalling-os.1345856/post-14579083. Hope it helps.

 

[nampramos]

Thank you!
Managed to do it, no issues.
cheers!

 

[duanepatrick]

You're welcome mate!