I have a Seagate 8TB SATA Drive that suddenly stopped being accessible. It only reports the drive as 3.9GB and the DATA is inaccessible. Have you seen this error before? Can you point me to the tools to troubleshoot this scenario even further?

Device Model: ST8000AS0002Serial Number: Z840D1DS
LU WWN Device Id: 5 000c50 087defe02
Firmware Version: AR15
User Capacity: 137,438,952,960 bytes [137 GB]
Sector Size: 512 bytes logical/physical
Rotation Rate: 7200 rpm
ATA Version is: ATA8-ACS T13/1699-D revision 4
SATA Version is: SATA 3.0, 6.0 Gb/s