2014 iMac Retina 5K - Reformatting

[Wxchaser]

I want to reformat my 2014 iMac Retina 5k - it has Boot Camp partition with Windows 10.

What is the best way to proceed? I would never use it again except for an external display or give it to my brother in law.

I need to remove it from my basement office to be replaced by my 2021 iMac M1 to make space in my upstairs office for a new Mac Studio, to replace my MBP M1 from 2021. I prefer a desktop to a laptop as I don't want to run in clam shell or docked mode & I travel with my IPP M4 instead of the MBP.

Thanks for any help.

 

[Mr_Brightside_@]

What to do before you sell, give away, trade in, or recycle your Mac - Apple Support (CA)

Reset your Mac to factory settings to prepare it for a new owner.

support.apple.com

 

[FreakinEurekan]

Boot with Command-Option-R. Let go of keys when the Globe comes up.
Open Disk Utility
Click Disk Utility menu > About Disk Utility. Version number should be 20.1. If it's not, start over (or it's not a 2014 iMac)
Click View menu > Show All Devices
Locate Apple SSD or Apple HDD or Fusion Drive (depending on how originally equipped; should be very top item) and click on it
Erase using scheme GUID, format APFS, name whatever
Disk Utility menu > Quit Disk Utility
Reinstall macOS

 

[Fishrrman]

If you're SURE you don't need any data that is on it, you can do this:

Boot to internet recovery.
Shut down first.
Hold down Command+OPTION+R DON'T LET GO OF THESE KEYS!
Press and release the power on button.
KEEP HOLDING THOSE KEYS DOWN!

You can let go when
- you see the "spinning globe" (ethernet connection)
or
- you are asked for your wifi password (wifi connection)

It takes a few mins for the utilities to load, be patient.

When you get to the Utilities, open disk utility.
IMPORTANT: go to the "view" menu and choose "show all devices".

Look at the "list on the left".
The "topmost" item should represent the physical drive inside.
We need to erase it.
Click on the top line that represents the drive (not the partitions below)
Then click "erase"
Select APFS, GUID partition format.
Then erase the drive.
(this will wipe out bootcamp and everything else)

You probably don't want to leave it that way, so we need to put a copy of the OS onto the drive, ready for the next user to set up.

So...
Quit disk utility and open the OS installer.
I think it will offer you OS 11 "Big Sur".
Go with that.
Start clicking through.
The Mac will reboot a few times, and the screen will go dark for a minute or more with no other indication of activity.
Just be patitent.

When done, you should see the initial setup screen.
You don't need to go any further.
Check the menu bar and see if you can "quit out of it" at this point.
If nothing's available there, just reach around the back, and press AND HOLD the power on button until the screen goes dark and the iMac shuts down.

It's ready for the next owner...
(heh, posted at the same time freakin did...)