Internal hard drive not mounting

If you need to recover files from the internal drive, then you have several options.

• Put laptop into Target Disk Mode so you can connect the laptop to another Mac.
• Remove the hard drive and connect it to another Mac using a USB to SATA Adapter, drive dock, or enclosure
• Install macOS to an external USB drive so you can boot the laptop from the external drive

https://support.apple.com/en-us/HT208496

• Contact a professional data recovery service such as Drive Savers or Ontrack both provide free estimates are recommended by Apple.

I suspect you may have a failing hard drive or a corrupt APFS file system (or both). If you can install & boot macOS from an external drive you can use DriveDX to check the health of the drive. Otherwise you can check the health of the drive by using a bootable Knoppix Linux USB drive created using Etcher (Mac/Windows/Linux). Option Boot the Knoppix USB drive and select the orange icon labeled "EFI". The computer may appear frozen on the boot picker menu while Knoppix boots so give Knoppix lots of time to boot.

Once Knoppix boots click on the "Start" menu icon in the lower left corner of the screen on the Taskbar and navigate the menus to "System Tools ---> GSmartControl". Within the GSmartControl app double-click on the icon for the laptop's internal drive to access the health report. Post the complete heath report here.

If the drive is failing, then the more you run it and the more you attempt to "fix" things the worse the failure will get where even a professional data recovery service may not be able to recover the data.

Hello Jfire7777,

Thanks for that info and for choosing the Apple Support Communities. If I understand correctly, you are unable to get your internal hard drive on your MacBook Pro to mount or show as available to reinstall OS X unexpectedly. To help with this, please try resetting the SMC and NVRAM on your Mac with the steps in these Apple resources, and then start up into Mac recovery mode and see if you can mount and run First Aid on your internal hard drive and then see if you can restart normally or reinstall the OS X software on your Mac:

Reset NVRAM or PRAM on your Mac

How to reset the SMC of your Mac

Disk Utility for Mac: Repair a disk using Disk Utility

How to reinstall macOS

Cheers!

What version of macOS is installed on this laptop? What file system was being used? Is Filevault enabled on the drive?

See if you can boot into Internet Recovery Mode using Command + Option + R. See if you can install macOS to an external drive. Then you can Option Boot the external drive to see if you can access the data on the internal drive.

Can you boot the Apple Diagnostics?

Since you can boot from the external drive run DriveDX and post the report for the internal drive here using the "Additional Text" icon which looks like a piece of paper. You need to determine the health of the drive before making any attempts to recover your data. If the drive is failing, then making attempts to recover the data will just make the problem worse where even a professional data recovery service won't be able to help.

Also, what file system is being used on the internal drive? Launch the Terminal app and run the following command and post the results here. Press the "Return" key at the end of the command to execute it.

diskutil  list  internal

Assuming you only ever had a single user account on the internal drive, then you should just be able to use the Finder to access the original user account on the internal drive to access your data. If you ever had more than a single user account, then you may not have permission to access the contents of the various folders (Desktop, Documents, etc.) within the original account. In that case you could just copy over the entire "Documents" folder (or other folders) to the external drive. Carbon Copy Cloner is a good app which can access any user account and allows you to select/deselect items to transfer.

This all assumes the internal drive can be mounted. If it cannot be mounted, then you may need to use a data recovery app such as PhotoRec, TestDisk, or Data Rescue, but only if the drive is healthy. If the drive is not healthy, then you should contact a professional data recovery service since standard apps (even data recovery apps) cannot handle the errors produced by a failing drive and you will just make it the problem much worse.

While the drive is healthy, the "Load Cycle Count" (attribute# 193) is almost exhausted at 15% life left. When I see this attribute exhausted I have seen drive issues occur mainly with performance, but also other odd behavior. This drive is unusual in that most drives allow for nearly 600K - 900K events where this drive will wear out after about 200K events (unless the RAW value for this attribute has been miscaculated). Regardless of whether the RAW value is accurate the normalized "Value" & "Worst" are what really matter here as they are at 15% life left. macOS is very rough on hard drives so you should consider replacing it with a new drive or an SSD.

At least you can now concentrate on trying to recover the data since I don't see anything which would cause me concern about the drive. If you are using an older version of macOS and the HFS+ file system, then you may be able to repair the file system using the paid app Disk Warrior. While Disk Warrior is a great app for repairing HFS+ file systems there are limitations to what it can repair.

If you are running an older version of macOS then the "internal" option may not exist. Try running the command like this so we can check which file system is being used on the drive:

diskutil  list

Is your internal drive accessible when booted from your external drive? Have you configured the Finder preferences to show mounted volumes on the Desktop and on the left side of the Finder window?

If the internal drive is not mounted, then have you tried using the data recovery apps I suggested earlier? If you use TestDisk or PhotoRec you will need to reference "disk0s2" which is your internal boot volume "Macintosh HD".

Sometimes you may need to manually mount the internal drive by using Disk Utility. Within Disk Utility select your "Macintosh HD" or "disk0s2" volume and click the "Mount" button.

Ok, your internal boot drive still shows up with the correct partitions which is good. Since your drives are using the HFS+ file system the paid app Disk Warrior is an option for you to try and repair the file system on your internal drive if the drive doesn't mount for you. It is up to you whether the cost of this app is worth it since there are no guarantees DW will be able to repair the file system. I would try all the other options mentioned first.