Can't wipe old 2008 iMac for recycling

You can create a bootable macOS 10.11 USB installer using the instructions in this Apple article:

https://support.apple.com/en-us/HT201372

I highly recommend you enable Filevault and let the encryption process completely finish. Then when you use Disk Utility to erase the drive you can follow the instructions exactly in this Apple article on how to prepare a Mac for sale or recycling so that you disassociate your AppleID from this computer and erase the drive:

https://support.apple.com/en-us/HT201065

This Apple article is a bit lacking since it assumes the hard drive is encrypted using Filevault or the user is using an SSD. If the hard drive is not encrypted, then a simple erase as suggested by Apple will still allow someone to use a data recovery app to recover personal data from the hard drive.

lpwhitley Said:

"Can't wipe old 2008 iMac for recycling: I'm finally trying to wipe my old 2008 iMac (OS X El Capitan 10.11.6) so I can bring it to Apple Store for recycling. It's won't give me the Disk Utility option to erase![...]"

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Mounting/Unmounting the Hard Dive:

1. Boot: in Recovery Mode [Hold Down: command + R keys]
2. Go to: Disk Utility
3. Tap the Hard Drive
4. Tap: the Mount button***.
5. Attempt this once more

***NOTE: If it is already mounted, then unmount it and then remount it

See where you can go from there.

Then remove the HD altogether. Should take you about 20 minutes. Here are some instructions:

https://eshop.macsales.com/installvideos/imac_24_0708e09_hd/