Fix 'Couldn't Open Disk 69879' Error During Erase Process

Erasing and formatting is a common practice when users perform to wipe the content on your partition or disk. But you likely encounter errors like "Couldn't open disk. : (-69879)" in Disk Utility or "Error: -69879: Couldn't open disk" in Terminal when you erase your external hard drive. This article from EaseUS will help you fix this error with several workable solutions.

First Aid: Recover Lost File in Accidental Erasure

Other than the unable to erase data errors, you may also come across data loss if you have unintentionally erased the wrong drive. And even if you forget to back up your important files, you can still restore your lost files from an external hard drive with professional tools like EaseUS Data Recovery Wizard for Mac.

• Recover files from the external HDD on Mac by utilizing the Command-Shift-Delete or Option-Command-Delete commands, which allow you to "Delete Immediately bypass Trash" and empty the Trash, respectively.
• After wiping the disk in Disk Utility, recover the formatted external hard drives on Mac. When logical faults arise on the external hard drive, support the recovery of audio, video, photos, documents, and other files.

Here is how you can recover your lost files from formatted or erased hard drives:

Step 1. Search for lost files

Correctly connect your external hard drive to your Mac. Launch EaseUS Data Recovery Wizard for Mac, and select the external hard drive. Then, click "Search for lost files" to find lost/deleted files on your external devices.

Note: Before data recovery, you'd better click "Disk Backup" from the left sidebar to create a backup of your external hard drive to avoid further data loss. After backing up the external hard drive, the software can recover data from your external hard drive's backup, and you can remove the external hard drive and use it again.

Step 2. Filter and find lost files

After the scan, all file types will be presented in the left panel. Select the file type to find wanted files on your external devices.

Step 3. Preview and recover

Click the file and preview it. Then, select the files you want to recover and click the "Recover" button. You can save your data to local and cloud drives.

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Fix 1. Unmount the Drive Before Using It to Fix Disk Error 69879

If the error message pops out after the unmounting disk step, you may first manually unmount the disk or partition before you erase it. Follow the steps here:

Step 1. Hold Command + Space and type Terminal to open this app.

Step 2. Copy and paste the following command 

Step 3. Run the following command after replacing disk_identifier with your disk info:

Now, you can erase your drive again.

Fix 2. Free Your Disk to Solve Couldn't Open Disk 69879

You can also erase the disk and leave it unformatted fiest and then reformat it with the file system. Do as follows:

Step 1. Launch Terminal and type the following command:

Step 2. Replace disk_identifier in the following command with your number and execute it.

Step 3. Now, you have successfully freed your diks and you can reformat the it again on Mac.

Conclusion

This article explains how to resolve the Mac issue "Couldn't open disk. : (-69879)" that may appear while trying to delete data from an internal or external drive. Use EaseUS Data Recovery Wizard for Mac if you're still interested in recovering data from the external device.

FAQs

Red this part to get more related information on this topic:

1. What is disk error 69879?

'Couldn't open disk 69879' fix When the Erasure Process Errors

This issue usually appears if there are write-protected, corrupted, or CoreStorage physical volumes on the internal or external drive that is being deleted. This can be a hassle, particularly if you have to wipe the drive in order to utilize it.

2. How to fix a writable disk is required (- 69772)?

• Verify if the drive is encrypted.
• Verify the permissions.
• Execute Disk First Aid.
• Delete the partitions.
• Delete the disk's recovery mode settings.