A little under 4 years ago I bought a Seagate Backup Plus Portable 5 TB external hard drive. It's worked fine for years, but recently it started having problems - it would disconnect and then immediately reconnect randomly. It would vanish from Windows and then a second later Windows would discover it again and present it as a newly connected drive. Being the colossal moron that I am, I didn't do anything about it, like backing up my data. I was busy and I didn't have the disk space.
Now I found out the disk is basically dead. I have tried 3 different cables, 2 computers, at least 5 different USB ports total. The disk doesn't show up in Windows Explorer, it doesn't show up in Disk Management, it doesn't show up in Device Manager. The little light on the side of the disk doesn't light up. The only indication that there might be something alive in there is that I can hear the disk humming when I put it against my ear as well as a slight vibration when I put my hand on it.
Now I know there are companies that specialize in recovering data from dead hard drives. However I really want to avoid doing that, as there's some pretty sensitive data on that disk. I may have to in the end, but before that I would like to ask, is there anything else I can do?
ddrescue
to make an image if you have concerns about the disk's integrity. From what you've said, I'd wager (hope) that the SATA to USB adapter is the issue here.