Raid 1 rebuild going wrong - please help!

Hi everyone! Today I bought a 4tb WD Red drive to replace the failed drive in a 8tb MyBook Duo RAID drive. I was hoping I could simply rebuild it, but after 4% of rebuilding the WD Drive Utilities software now says RAID Status: Rebuild Failed, even though underneath that it says Drive 1 Status: Rebuilding. Very confused and not sure what to do?

The main LED is slowly blinking red, and the Drive 1 LED is permanently red.

Hi lukeblazejewski,

As the drive 1 failed, you should take a backup of drive 2 and rebuild RAID of complete My Book Duo to initialize the device from the start.