74 Macworld • December 2019FEATURE
erase and reinstall macOS, or even on logging
in, depending on what state the Mac was left in
when you purchased it.
The best way to buy a Mac is after the seller
has erased the drive and installed a fresh copy of
macOS on it without yet completing setup, so you
can do that from scratch without worrying about
any software they may have installed or passwords
or accounts they’ve created. And the best scenario
to receive a used Mac is to do so in person, so you
can fire up the computer and see it’s working, run
through tests listed below, and be sure no extra
passwords or permissions are needed. Regardless
of how you receive the Mac, check out these items
– preferably before finalizing the deal.- Shut the Mac down and perform a ‘cold boot’ –
start it up and see if you can log in with account
informationprovidedorcompletemacOSsetup. - Restart normally from the Finder and hold down
Command-R to make sure you can start up in
macOS Recovery. (If macOS Recovery isn’t
installed, the Mac should attempt to retrieve
it over the internet and install it. If shown a
lock icon and password field by itself, see the
firmwarepasswordsectionbelow.) - In Recovery, run Disk Utility. Can you mount the
disk without a password? And run Disk First Aid
to ensure that no problems are reported.
That covers the basics, but you can and should
dig deeper. (You should also use this checklist