Home > Questions

Couldn't modify partition map because file system verification failed. (-69803)

As I tried to partition a 3TB drive into a 2TB partition for Time Machine and a 1TB partition for specific files backup, I get this error: Couldn’t modify partition map because file system verification failed. Please verify and repair each volume individually and then try again. : (-69803) Operation failed. When I run First Aid on the drive, I get this error, "An internal error has occurred. : (-69610) Operation failed." How do I fix it?

Best Answered by

iBoysoft author Jenny Zeng

Jenny Zeng

Answered on Tuesday, January 27, 2026

The error "Couldn't modify partition map because file system verification failed. (-69803)" and "An internal error has occurred. : (-69610)" may indicate that your external hard drive's partition map is corrupted, unknown or missing. This may be caused by incorrect operations, such as deleting the EFI system partition.

To fix it and be able to partition your external hard drive into your intended partitions, you can format your drive in macOS Recovery.

  1. Eject or unmount your external hard drive, then unplug it or turn off it and keep it plugged in.
  2. Restart your Mac, then press and hold Command + R immediately after your screen turns black. (M1 Macs have a different way to enter macOS Recovery.) 
  3. Release the keys when the Apple logo appears.
  4. Go to Disk Utility > Continue.
  5. Turn on your hard drive or reconnect it to your Mac.
  6. Click View > Show All Devices.
  7. Select your external drive's physical disk and click Erase.
  8. Run First Aid to repair the disk and then the volume.
  9. Repartition your drive.

Read Also:

Fix 'Couldn't modify partition map' on Mac (69874 & 69803)

[Fixed] Can't Partition SD Card/USB Drive/Hard Drive on Mac?

 

People Also Ask

Read More Questions

Read More Advice From iBoysoft's Computer Experts

Disk Utility won

[Fixed] Disk Utility Won't Let You Erase Hard Drives

Guide to resolve problems when Disk Utility won’t let you erase hard drives or SD cards because the erase button is grayed out or the “Erase process has failed” error pops up.

What is macOS Tahoe 26

macOS Tahoe 26: Beta, Release Date, Compatibility & Review

A post summarizes macOS 26 Tahoe, including the downloads and release date, compatibility, and main new features.