I am trying to recover data from a bad Seagate 1TB hard drive in a 2010 iMac. One day the iMac wouldn't boot (stuck at gray screen on startup). I removed the hard drive from the iMac and connected it to a MacBook using a 3.5" HDD to USB adapter. The hard drive wouldn't mount but it did display in Disk Utility that that there were 2 partitions on the disk. I tried to run Disk Warrior and it showed thousands of errors but still wouldn't mount. At this time the hard drive only show one partition in Disk Utility. Next I tried putting the hard drive in a desktop PC and running Spin Rite - which then gave me several division overflow errors (even with running Spin Rite with a newer version of DOS). The SMART status on the drive reports that the drive has had failures and HD Tune referenced the drive had once hit 59 degrees celsius. Disk Utility gives me the following message when running a pair: Error: Disk Utility can’t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files.

Overall, the hard drive spins up and sounds OK - there are no clicking noises but the hard drive won't mount and displays as a light gray "Macintosh HD" in disk utility. Any tips or advice on how to recover data on this drive would be GREATLY appreciated! Are there any other tools I can try before calling it quits on this drive?

Thank you