PR4100 new disk not accessible but shows good status

Hi everyone.

Problem: A new 6TB WD Red drive shows in Disk Status as good but is inaccessible. The disk LED status shows solid red.

Background: I bought a PR4100 and installed a 6TB WD Red drive into slot 2 and physically transferred a 4TB WD Red drive from a My Cloud device into slot 1. I successfully set the 4TB drive to roaming and all data are accessible. The LED light is solid blue about six hours after installation. RAID appears to be set to JBOD, which is what I believe that I want. It’s as if the 6TB drive doesn’t exist.

My desired solution is one where I can access and use the drive as additional storage to the 4TB for a total of 10TB. I do not want to do anything that will erase data on my 4TB drive.

It seems that new 6TB WD Red is not accessible in My Cloud PR4100 enclosure. You should check the diagnostic status of My Cloud PR4100 after accessing the dashboard and run Quick & Full Test to check the health of connected internal drives in enclosure.
Also, you may also run System test to check the health of the hardware on the device, such as the hard drives, fan, system clock, and device temperature.

Thanks for responding with your suggestions. I ran the quick test and it would not complete. Then I saw that others had to turn off Remote Access in order for the tests to complete. I did that and then ran the quick test, which finished and indicated there are no errors associated with either drive (4TB or 6TB). The full test never completes. It makes it about 5-10% of the way on the bar and does not complete. I’ve allowed it to run overnight several times without success.

The full test finally completed and delivered these results:

Self Test Results


Passed - Full disk test completed successfully.


Failed - Full disk test failed. Please backup your data and replace this disk. If you need further assistance, contact WD Support.

Disk 1 is my 4TB that I moved from a previous My Cloud and Disk 2 is my new 6TB disk.

I sent it back to Amazon.