need to rest fusion drive to its original

Copy the selected text to the Clipboard by pressing the key combination command-C

Where in sams name is "The Clipboard"? When I do what you say "Command C" I get nothing? No Clipboard pops up nothing. What do you mean. I'm running OS Sierra v10.12.4 And I'm having trouble locating this Clipboard you reference, where is it?

Please read this whole message before doing anything. If you don't feel confident that you can follow the instructions, get someone more experienced to help you. One option is to make a "Genius" appointment at an Apple Store.

This procedure applies only to an iMac or Mac mini with a factory-installed Fusion Drive.

You'll need to refer to these instructions while no web browser is running, so either print them or load them on another device before you begin.

1. All data on the internal drives will be removed, including Boot Camp data, which is not backed up by Time Machine. You need at least two complete, independent backups. One backup is not enough to be safe. There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

2. Disconnect all external storage devices.

3. Start up in Internet Recovery mode by holding down the key combination command-option-R at the startup chime. Release the keys when you see a spinning globe. Select a language, if prompted.

Note: You need an always-on Ethernet or Wi-Fi connection to the Internet to use Recovery. It won’t work with USB or PPPoE modems, or with proxy servers, or with networks that require a certificate for authentication.

What happens next depends on what version of OS X came preinstalled on your model (and therefore, which version of Disk Utility is included in Internet Recovery):

☞ If the machine came with OS X 10.10 ("Yosemite"), 10.9 ("Mavericks"), or 10.8 ("Mountain Lion"), please take Step 4a and skip Step 4b.

☞ If it came with OS X 10.11 ("El Capitan") or a later version, go to Step 4b.

If you don't know what version of OS X the machine came with, look it up on this page.

After taking whichever of those steps is applicable, you should have an empty Fusion Drive named "Macintosh HD" on which you can carry out either Step 7 or Step 8.

4a. Repair the Fusion Drive (see under "Troubleshooting" on the linked page.) Quit Disk Utility and go to Step 7a or Step 7b. Skip Steps 4b, 5, and 6.

4b. In the OS X Utilities screen, select Get Help Online. Safari will launch. While in Recovery, you'll have no access to your bookmarks, but you won't need them. Load this web page.

5. Triple-click anywhere in the line below to select it:

N=Macintosh\ HD; for d in /dev/disk?; do o=`diskutil info $d`; [[ ! "$SSD" ]] && grep -lqw 'APPLE SSD' <<< "$o" && SSD=$d; [[ ! "$HDD" ]] && grep -lqw 'APPLE HDD' <<< "$o" && HDD=$d; [[ "$SSD" && "$HDD" ]] && break; done; diskutil cs create "$N" $SSD $HDD && diskutil cs createLV "$N" jhfs+ "$N" 100%

Copy the selected text to the Clipboard by pressing the key combination command-C.

Quit Safari. You'll be returned to the OS X Utilities screen.

6. From the menu bar, select

Utilities ▹ Terminal

The Terminal application will launch. Paste into the Terminal window by pressing the key combination command-V. Wait for a new line ending in a hash sign (#) to appear. If nothing happens, press the return key.

Quit Terminal to be returned to the main screen.

7a. If you have a Time Machine backup, connect the backup device and restore your data. If you backed up to a network device such as a Time Capsule, it should be connected automatically.

7b. If you don't have a Time Machine backup, or if you can't restore from the Time Machine backup that you do have, install OS X. Restore the data afterwards in Migration Assistant.

In Internet Recovery mode, you'll be installing the original version of OS X that shipped with the machine. If you've upgraded the OS in the App Store, and you want to install the latest version, then before you install, restart in local Recovery mode by holding down the key combination command-R (not the option key) at the startup chime. When you install the OS, you'll be prompted for the Apple ID and password that you used to upgrade.

Thank you. Apple support couldn't get me going again. Found your post and gave it a try. Now I don't have to lug my iMac to the store.

Thank you for posting this fix it has helped me so much

Regards

Warren