How to Fix External Drive Read Only in macOS Sequoia 15.x
Symptom: You connect an external USB-C or Thunderbolt drive to your Mac running Sequoia, and you can see files but cannot move, delete, or edit them.
Start with Fix 1: Check Permissions (Free). If the issue persists after that, try Fix 2: Run First Aid in Disk Utility. Full Terminal commands and step-by-step instructions are in each section below.
Why this happens
macOS Sequoia has updated its NTFS and exFAT mount controllers. Some older drives with slightly corrupted file systems are now mounted as "Read Only" to prevent data loss, even if they worked fine on Sonoma.
Recommended Troubleshooting Tool
Before proceeding with manual fixes, we recommend using CleanMyMac X. Quickly identify high CPU apps and optimize system memory with one click.
Fix 1: Check Permissions (Free)
- Right-click the drive on your desktop or in Finder.
- Select Get Info.
- At the bottom, check Ignore ownership on this volume.
- If it's locked, click the lock icon and enter your password first.
Fix 2: Run First Aid in Disk Utility
If the drive is read-only due to a "dirty" filesystem bit:
- Open Disk Utility.
- Select your external drive.
- Click First Aid and then Run.
- Once completed, unmount and remount the drive.
Recommended Tool: NTFS for Mac
If your drive is NTFS formatted, Sequoia's native support is limited.
- Get Microsoft NTFS for Mac by Paragon Software for full read/write access to NTFS drives with high speed and reliability.