I'm running OS X El Cap. I have a 1TB WD Black 3.5" drive that has been in an external USB 2 enclosure for years. These were purchased separately, not as an "external hard drive". A few weeks ago the drive started having issues where it would un-mount itself. It's possible my dog bumped it under the desk, or maybe a power surge. I read online lots of folks had this issue...I've tried few things but for past 3 weeks I have not been able to get the drive to mount. Well, it has mounted for maybe 10 seconds on a few occasions. I've tried three other enclosures. One is exactly the same as the first, one OWC dual bay and one of those "just the cables" things. The drive won't mount at all in these others. It doesn't even seem to spin up. I've tried the first enclosure via FireWire 400 daisy chained to a FW800 enclosure that is connected to my iMac. Drive won't mount. The drive powers and seems to spin up in the original MacAlly enclosure. It just won't mount. So...any ideas? Any way I can get the data off this drive? It has movie files and my iTunes library. I was not backing this up... I have Disk Warrior but I can't even mount the drive so not sure what to do.