Cant see my External Drive anymore

Hi everybody

I ve got the Passport with USB 3.0 and I use it on my mac…but its not originally the Mac Version of WD!

Now while i was copying Data on my WD at one point it just stopped because it said that my Passport is not connected anymore. So i reconnectet it, entered my password, but nothing happend. I couldent see the Drive in the finder nor was there the WD unlocker. But the Drive is still vibrating and working! Whats the matter with that?

what can i do? I need it quite urgently!

Thanks for all your help

Cheers

Check if the drive appears on disk utility

try restarting the PC and a different port on the Mac