If you can’t see Macintosh HD or SSD in Disk Utility

Your built-in startup disk should be the first item listed in the Disk Utility sidebar. It’s named Macintosh HD unless you’ve changed its name. If you can’t see it there, choose the Apple menu  > Shut Down, then unplug all non-essential devices from your Mac and try again. If still can’t see the disk then follow the steps below:
Looking for how to solve the problem, please tried to clean the NVRAM, with ALT + CMD + P + Q. NVMRAM was successfully cleaned but the issue was not resolved! Now try the below steps which may help to find out your internal Mac HD or SSD:

Start up from macOS Recovery:

Turn on your Mac, then immediately press and hold Command (⌘) and R until you see an Apple logo or other image.

If asked, select a user you know the password for and enter their administrator password.

From the utility window, select Disk Utility and click Continue.

Select Macintosh HD in the sidebar of Disk Utility. Can’t see Macintosh HD?

Check the disk on Terminal Command Line:

Turn on your Mac, then immediately press and hold Command (⌘) and R until you see an Apple logo or other image.

If asked, select a user you know the password for and enter their administrator password.

Click the utility menu, and select Terminal to  Continue.

Write ” diskutil list” then hit the return key. You will see the following kind of list in the image. However, if you still can’t see the internal HD or SSD then its means there is something wrong with your Mac hardware/ disk drive.

diskutil list

If your disk still doesn’t appear in Disk Utility or Disk Utility reports that the erase process has failed, your Mac might need service. If you need help, please contact our support center at https://mymaccomputer.com.au/imac-repair-upgrade/