Is there any chance of data recovery? TIA.

I used a different connector, and that didn't help. While unmounted, the volumes file system is inaccessible by regular reads and writes. I unplugged it while the computer was off, and then restarted, and then plugged it back in, and that didn't help. When a volume is unmounted, its drive letter is unassigned and may be used by another storage device. I tried restarting a few times, which did not help. Upon restarting my computer, the Mac won't recognize my external hard drive in Finder or in Disk Utility.

So, I manually shut it down with the power button. All applications stopped responding, force quit worked but the spinning wheel of death remained and couldn't open any new programs. Once I was finished with it, I clicked 'eject' and the spinning wheel of death came up. original issue- I was accessing my perfectly good, relatively new external hard drive on my Macbook Pro. use the following 2 commands: diskutil unmountDisk /dev/disk2s2 diskutil eject /dev/disk2s2 Eject was successful! Unplugged it, replugged it back in, and eureka! All of my files safely stored. Identify the disk you would like to unmount (for me it was disk2s2) 4. SOLVED! For posterity for anyone who might Google this in the future, this is what works: 1.

Volume could not be unmounted