Help - Can't Unmount Internal HD for Formatting and Selling iMac

[turnipfarmer]

Hey Everyone

Can anyone help or shed any light on this issue?

I am wanting to format my internal HD on my iMac ready for selling, I booted into recovery mode and used Disk Utility but every time I want to erase the HD it won't and says it can't unmount the drive.

I have tried FirstAid and that hasn't fixed it either.

Anyone got any tips on what I can do?

 

[Amsterdamned]

I may be reading this wrong but isn’t the recovery partition on the drive you’re trying to wipe? Create a USB installer, boot from that and you should be good to go.

 

[turnipfarmer]

I may be reading this wrong but isn’t the recovery partition on the drive you’re trying to wipe? Create a USB installer, boot from that and you should be good to go.

Yeah that's what I thought in the end, never done this on a Mac before. Created a boot disc onto USB stick via CCC in the end and booted off that and now it's formatting the internal drive.

Now once this is done, do I just tell it to install fresh install of osx and I presume I can tell it to install on the internal drive? It won't preselect the usb stick as I booted off it?

 

[Amsterdamned]

Once you start the fresh install you should see your newly-formatted drive. Select that and you’re golden 😬

 

[mj_]

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

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

support.apple.com