Erase button is grayed out for Fusion Drive in iMac

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Level 2

188 points

Erase button is grayed out for Fusion Drive in iMac

I'm trying to erase the fusion drive in my Late 2015 iMac with Intel chip. I just want to recycle it, without reinstalling an operating system. I did all the recommended steps on the old computer: signed out of Apple ID, etc. I went to Disk Utility, and clicked on the Macintosh HD. The erase button is grayed out. How can I erase the drive? By the way, for whatever reason, they old iMac is not recognizing there bluetooth keyboard and trackpad that were previously connected before I connected them to my new iMac. I tried turning off bluetooth on the new iMac in case it was interfering with the bluetooth on the old iMac, but that didn't help. So I'm using TeamViewer on my iPad to connect to my old computer and doing everything from my iPad. As such, the keyboard on my iPad does not transmit keystrokes to the old iMac, so I can't use keyboard combinations to issue commands.

[Re-Titled by Moderator]

Original Title: "Erase" grayed out

iMac 27″

Posted on Oct 12, 2025 12:23 PM

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Answer 1

HWTech

Level 9

68,198 points

Oct 12, 2025 2:25 PM in response to jla930

You cannot erase the drives you are using to boot the system. You need to boot into Recovery Mode or from a bootable macOS USB installer.

In order to make sure your personal data is destroyed, you need to make sure to securely erase the Hard Drive portion of the Fusion Drive. The easiest method is to enable Filevault & let it finish encrypting before you go to erase the system. A simple erase will then be enough to destroy the encryption keys which in turn destroys any possibility of recovering data from the Hard Drive. Unfortunately Apple has forgotten that many people still have working older Macs containing Hard Drives (and Fusion Drives) so Apple doesn't give the proper instructions for securely erasing their personal data. Once Filevault has finished encrypting, then you can follow Apple instructions in the following Apple article to erase the system & reinstall macOS (assuming the Hard Drive is still healthy enough to finish encrypting its data):

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

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Answer 2

rkaufmann87

Level 10

148,422 points

Oct 12, 2025 4:06 PM in response to jla930

HWTech is 100% correct, please carefully read the advice and follow to the letter. It is best to access the Recovery Partition though. If you do not know how to do that restart the computer into the Recovery Partition, just power down and then press the power key on the back of the computer and immediately hold down Command + R .

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Answer 3

jla930 Author

Level 2

188 points

Oct 13, 2025 6:03 PM in response to jla930

@HWTech, @rkaufmann87, Thanks for your replies. As I mentioned in my original post, I have no ability to send keystrokes to the old iMac. I could go out and buy a cheap wired keyboard and mouse, I suppose. It’s very disturbing to me that the very same Magic Keyboard and Magic Trackpad, both Bluetooth, both used on the old iMac, suddenly don’t appear in the list of Bluetooth devices seen by the old iMac. I turned off Bluetooth in the new iMac, thinking I had reached the maximum number of devices that the keyboard and trackpad would work on, but still not recognized by the old iMac. If I was still using it, I’d post a new thread in another category about it. I’m not the type of person who can just shrug their shoulders and dismiss something not working for unknown reasons, especially with Apple products that are known to work well. The other guy, yeah. I used to work in I.T., and dealt with many employee hardware and software issues. When something strange would happen to someone’s operating system, or to an application made by the same guys, and the user asked me why it happened, my answer was always the same: “It’s a M******** product.” You know what I mean. It was the only explanation I had, and always seemed to be the correct one. But Apple hardware and software is a universe above that. That’s why I’m frustrated at the failure of the old iMac even seeing the keyboard and trackpad Bluetooth devices. It’s not expected.

Sorry for my little sidebar. Anyway, I’ll purchase a cheap wired keyboard and mouse set and hook it up to the old iMac and go from there. Thanks again.

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