I copied a number of Adobe Premier Pro movie files and some mixed Pro Tools files onto a WD My Passport Slim from my Mac Pro in order to work on them on vacation. When I plug the external drive into my MacBook it won't mount. The power light is on so I know the drive is getting power through the USB cable. At one point it appeared in disk utility but I could not alter it at all. Now it's not showing up at all.Tried to install the "My Passport"drivers from WDC but it won't load properly either (just gives me a "not responding" message). I am running Sierra on this MacBook and the drive itself is formatted to FAT32 so everything should load properly. And yet!! Any tips would be appreciated.
Follow the diskutil advice... if it’s listed in Diskutil, you can try the mount command. You can also check to see if the drive is listed within “about this Mac”. Click on more information and scroll down to USB, the drive should be listed there.
The is a utility app called Mountain which gives you much-improved control over all your volumes. You may want to try it to see if it will mount your drive. I use it to mount and unmount drives and it works well. The only problem is it's $6 from the above site. The above site has an unusual front page. Be sure to hit the Continue button near the bottom of the page to read about Mountain or to orfer it.