MyBook 4TB drive appears in System Information. It appears in Disk Utility, but is “grayed out,” i.e., not able to mount, not able to run Disk First Aid on it. The drive is running, because I can hear it. Nearly 4 TB of data that is totally useless to me if I can’t access it.
Please contact the WD Technical Support team for best assistance and troubleshooting:
There are several reasons for a WD My Passport hard drive going invisible or greyed out on a Mac system:
- Corrupt partition table
- APFS or HFS file system
- Cryptic Disk errors
- Hard drive faulty cable
- Wear and tear
- Failed Restore
- Bad blocks on the surface
- Failed Partitioning on External Drive
Further, I suggest you to check the below link for solution to fix the issue:
Hope it helps!