This message usually appears if the files on the drive are in use, e.g., the System drive, and ChkDsk is unable to execute. While you can always force the volume to dismount or invalidate all open ...
TLDR: Seagate 2TB drive is not powering on or showing up in windows after running a long chkdsk /f. I'm thinking of sending it away to a recovery specialist. System - Windows 10, Asus P8P67 Deluxe ...