No Admin Account, Reset Set up, Remote Managment connection fails

I'm working on getting the Remote Management removed for the device as it was bought from a family member who bought if from their work who controls the Remote Management for the device.

As you can imagine Remote Management complicates matters. First please try the following in an attempt to establish a temporary Admin account for the sole purpose of re-enabling Admin rights on your usual Account.

If it doesn't work, then you will need to erase the Mac and reconfigure it. That procedure starts with "To properly sell or transfer ownership of a Mac."

If there are no longer any User Accounts with Administrator privileges on your Mac, then please read and follow these instructions.

Read the lengthy procedure that follows. You should probably print it vs. writing down the steps or trying to repeat it from memory. Don't be put off by the length of the instructions. Some of the steps are optional. It's simple and will only take a few moments.

It is also overly conservative, but I have used it myself recently and I know it will work.

As I understand it, you have a Mac with no Administrator accounts. Of course that is not supposed to be possible, but if that really is the case you can use the following technique to create a new, temporary Administrator account, the sole purpose of which will be to log in as an Administrator that can give your normal account Admin privileges.

There may be other techniques to recover from the "impossible" circumstance in which you find yourself, but the following is one that I have successfully used in the past.

Please read everything that follows before continuing. If you have only the one computer you will need to print this for reference.

Prerequisites:

• If you have not done so already, create a reliable backup in the event something unexpected occurs.

  To learn how to use Time Machine please read Use Time Machine to back up or restore your Mac - Apple Support.

• If you configured an EFI Firmware Passwordthat will preclude recovery, unless you know that password.

  A Firmware Password precludes starting a Mac in single-user mode, so you will need to temporarily remove it before continuing.

• If you encrypted your startup volume with FileVault, its password will also be required to unlock the disk.

  That password may or may not be the same login password you have been accustomed to using.

Confirm each of the above prerequisites before continuing.

Then,

• Power on or restart your Mac.
• At the chime or grey screen, hold ⌘ and S on your keyboard (two fingers) to enter single-user mode.
• At the localhost:/ root# prompt, type

fsck -fy

...and press Return.

This is a simple check for file system integrity and is optional. It may take a few minutes to complete during which time various messages will appear. None of them are relevant unless they indicate some unrecoverable error. Be patient. If you get concerned that the system has stalled or become unresponsive press the Return key. Nothing will happen other than to echo the Return character, advancing the text on the screen, confirming your Mac has not completely frozen.

When the integrity check completes pressing the Return key will result in the localhost prompt again, waiting for your input.

At the localhost:/ root# prompt, type each of the following lines, exactly as written, including capitalization, one line at a time, each line followed by the Return key. There is a single space preceding the first "slash" ( / ) character in each line:

mount -uw /

rm /var/db/.AppleSetupDone

reboot

The Mac will restart, and then take you through the entire setup and registration process that you have not seen since you originally unboxed it. Do not be concerned—none of the above deletes any information. All your pre-existing user accounts will still available, assuming they were intact prior to beginning this procedure.

Do not elect to transfer your information from another Mac: When the "Transfer Information to This Mac" screen appears, select "Do not transfer any information now" and press Continue.

At the "Create a Computer Account" screen, create the new, temporary account using a different "Full name" and "Account name" than the one you already use. Remember the password you select. Provide a password hint if you wish. You don't have to sign in to iCloud or anything else you might decide to do if you wanted to use that User Account for anything else.

"Allow this Account to unlock the disk" will be selected by default, so confirm that it is because that's the key to fixing the problem.

When it completes, log in under that new account. Use System Preferences to change your normal account to "Allow user to administer this computer". Log out, log in under your normal account and verify you can use it without restriction.

After that, you can safely delete the temporary account you just created by following these instructions: Delete a user or group - Apple Support. Before removing it, confirm you don't need any of the files you might have created in that Account.

If MDM continues to be a roadblock then proceed below.

To properly sell or transfer ownership of a Mac, even to someone in your family, you must follow these instructions.

Refer to What to do before selling or giving away your Mac

1. If you enabled FileVault, disable it in System Preferences > Security & Privacy.
2. "Deauthorize" your iTunes account. Same for Audible if you have one.
3. System Preferences > iCloud > de-select "Back to My Mac" and "Find my Mac".
4. Sign out of iCloud. Select "Delete from Mac" when it appears.

Next: Remove all your personal information by completely erasing the Mac's internal storage.

1. If your Mac shipped with a grey System Install DVD, start your Mac with that disc inserted in the optical drive while holding the c key to boot from it instead of its internal volume, which should be erased before selling it.

   Apple stopped shipping Macs requiring those discs in August, 2011.

2. If your Mac did not ship with discs, boot OS X Internet Recovery:
   • using four fingers press and hold the following keys: Shift, ⌘ (command), option, and R.
   • With a fifth finger press the power button to turn on the Mac.
   • Keep the other four fingers where they are until you see the "spinning globe" icon.
   • This method forces the Mac to download its originally installed OS from Apple's servers, which will not require an Apple ID to install.
3. Remove any Open Firmware password if you created one: select Firmware Password Utility from the Utilities menu and remove it.
4. Select Disk Utility from the Utilities menu.
5. Remove any partitions you may have created.
6. Select the Mac's hard disk icon (not the volume beneath it), then select the "Erase" tab.
7. Select the "Security Options" button and erase the disk.
   • The more "securely" you erase the disk, the longer it will take.
   • The fastest method is sufficient since all but the most expensive techniques and equipment will be able to recover securely erased data.
8. When it finishes, quit Disk Utility.
9. Select Install Mac OS X from the Utilities menu.
   • An Apple ID will not be required. If a prompt for an Apple ID appears, return to Step 5.
   • Do not create any user accounts.
10. When it finishes, shut down the computer.
11. If you want to install the bundled apps that were included with your Mac, restart by using your Applications DVD if one was included, and install the bundled apps.
    • Apps bundled with newer Macs that shipped without discs cannot be transferred. Its new owner must purchase them from the Mac App Store using his or her own Apple ID.
    • Those apps (Pages, Numbers, Keynote, GarageBand, and iMovie) are now free.

If the Mac is being sold to someone outside the family consider the following additional information:

1. System Install DVDs that came with your Mac should remain with it forever, and must be included with the sale.
2. Consider including your AppleCare certificate if you bought it, printed documentation, even the box if you still have it.

   AppleCare stays with the equipment and is transferable.

3. Execute a bill of sale showing the Mac's serial number.
4. Once no longer in your possession, remove the Mac from your devices in My Support Profile.

Thank you so much John Galt, yesterday I spent the whole day chatting and talking on the phone with Apple tech support agents with no avail whatsoever, until I followed your steps. You sir are a Godsend!