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Have trouble erasing a drive on your Mac? You might not know what to do when you get the feared "Couldn't Open Device -69877" error. Don't worry, though! This guide gives you all the necessary information to fix this problem and correctly format your storage device.

Fix the Error: Couldn't Open Device 69877

We'll investigate the possible causes of this message, which could be anything from temporary software bugs to problems with permissions. Now that we know what to do, we'll look at a step-by-step way to fix the mistake. We'll begin with easy changes, like restarting your Mac, and move on to more complex ones that use Terminal commands while ensuring your important data stays safe.

Let's fix this problem and get your Mac back to erase drives!

Understanding the Error: Couldn't Open Device 69877

The error number -69877 doesn't give a clear reason, but it usually means that your Mac and the drive are having trouble talking. Some possible reasons are:

  • Permissions Issues: Disk Utility may be unable to view and change the targeted drive if it does not have the right permissions. It can happen because of limits the user sets or system permissions problems.
  • Hardware Connectivity Problems: The 'Couldn't Open Device 69877' error can be caused by hardware that isn't working right or is hooked incorrectly, like USB cables or external drives. Problems like loose connections, broken ports, or gear that doesn't work with the eraser could slow it down.
  • Drive Corruption or Damage: If the drive being erased is damaged, corrupted, or has bad sectors, Disk Utility might not be able to open it correctly, which would cause the mistake we're talking about. For these kinds of problems, you need to take extra steps to fix the drive problems at their source.
  • Software Glitches or Compatibility Conflicts: This mistake can also be caused by bugs in the system software, problems with third-party programs, or problems with Disk Utility's interaction with the Mac operating system.

Before We Begin: Essential Precautions

  • Data Backup: When you erase a drive, everything is erased. Ensure you have a current copy of any important files on the drive you want to delete.
  • Identify the Target Drive: Ensure you're erasing the right drive in Disk Utility so you don't accidentally erase important storage.
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Methods to Fix the Error: Couldn't Open Device 69877

We'll look at several approaches, going from the easiest to the most complex. It is suggested that you try them in this order:

1. Check Permissions and Ownership:

Find the drive in question and check its rights. Make sure that your user account has the right to view and change the drive.

To change rights, choose the drive, go to the File menu, and click "Get Info." Then, change permissions under "Sharing & Permissions."

To prove your identity, pick the drive and click the lock icon to take ownership of it if needed. Then, give your user account the right powers.

Fix the Error: Couldn't Open Device 69877

2. Restart Your Mac:

A simple restart is often all it takes to fix short-term program problems. You may only need to do this to allow Disk Utility to view the drive and communicate with it.

3. Re-mount the Drive:

The link between the drive and Mac may not always work properly. To fix this, safely remove the drive, then put it back in and try to erase it again.

4. Verify Disk Utility Permissions:

If the rights are wrong, Disk Utility might be unable to change the drive. How to deal with this:

  • Start Terminal by going to Applications > Utilities.
  • Type the following number and hit "Enter": Replace /dev/diskX with the drive's real name, which you can find in Disk Utility, and then run the command "sudo diskutil repairPermissions /dev/diskX."
  • When asked, type in your user password.
  • When you're done, use Disk Utility to erase the drive again.

5. Reset PRAM/NVRAM (For Intel-based Macs Only):

Hardware settings at the low level are controlled by the Parameter RAM (PRAM) or NVRAM (Newer Macs). Resetting them can sometimes fix problems with communication:

Resetting PRAM/NVRAM:

6. Boot into Recovery Mode and Use Disk Utility:

You can access a different macOS version with Disk Utility when you start in Recovery Mode. It can help get around short-term problems with the main macOS installation:

  • Start up your Mac again.
  • To start up, hold down the Command and R keys til you see the Apple logo or a globe spinning. If you are a Mac with Apple silicon, press and hold Power button to enter into macOS Recovery mode, select Options and click on Continue button.
  • From the Utilities menu, choose Disk Utility once you are in Recovery Mode and then erase the drive.

Fix the Error: Couldn't Open Device 69877

7. Boot into Internet Recovery Mode (For More Persistent Issues):

This mode gets a new copy of macOS from Apple's computers, which might fix software conflicts that are stopping Disk Utility from working:

  • Start up your Mac again.
  • Hold down the Command, Option, and R keys during start-up until you see a globe spinning.
  • If necessary, follow the on-screen steps to connect to Wi-Fi. Then, erase the drive with Disk Utility.

8. Format the Drive Using Terminal (Advanced Users):

You have more control over the formatting process this way, but be careful because any mistakes can cause data loss:

  • Start up Terminal.
  • Use Disk Utility to find the target drive's name (under the "Identifier" column).
  • Type the following command, changing "FORMAT" to the format you want (for example, "APFS" for Mac or "exFAT" for other platforms) and "/dev/diskX" to the name of your drive: format /dev/diskX with diskutil eraseDisk
  • When asked, press Enter and type in your user password.

If you have lost data due to erasing hard drive on Mac, just use Mac data recovery app to scan the drive and get all lost data back.

Recover Erased Hard Drive on Mac

Recover Erased Hard Drive on Mac

Do Your Data Recovery for Mac can help you recover lost data from a HDD/SSD which is erased by Disk Utility.

9. Verify Hardware Connections:

If you're working with an external drive, ensure it's tied to your Mac safely. If you still have trouble connecting, try using a different USB port or cord.

Check if the drive or the wires that connect it are broken. If you need to, replace any broken parts.

How to Wipe A Drive That Won't Be Erased in Disk Utility

If you can not erase the hard drive by using Disk Utility, you can try third-party disk formatting tool - such as DoYourData Super Eraser for Mac. It can help you wipe NTFS/APFS/HFS/ExFAT/FAT32 or RAW drive on mac.

Step 1. Download and install DoYourData Super Eraser for Mac on your Mac, then open it.

Step 2. Open DoYourData Super Eraser for Mac and choose Wipe Hard Drive mode, this mode will format and wipe the selected drive and permanently erase all data from it.

can’t erase a hard drive on mac

Step 3. Select the drive and then click on Wipe Now button.

can’t erase a hard drive on mac

Note: Once the data is erased by DoYourData Super Eraser for Mac, the data is lost for good, can not be recovered by any method.


When trying to erase drives on a Mac, getting errors like "Couldn't Open Device 69877" can be annoying, but most of the time, the problem can be fixed by following the right steps. By knowing what might have caused the error and using the solutions described in this article, users can easily get past this problem and continue their drive maintenance tasks. Remember to be careful when working with drives to keep your data safe and the security of your storage devices.

DoYourData Author

Written & Updated by Ricky Lin

Ricky Lin is an senior editor of DoYourData who lives in Adelaide, Australia. He is interested in writing technology articles related with data recovery, computer issue fixes, disk clone, iPhone data recovery, video edit, Mac optimization, etc. He Joined DoYourData in 2019 and have written 500+ articles to help both Windows users and Mac users to solve data or computer problems.

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