My passport 1TB is not recognized on USB 3.0 port

hi joe,

 im joeper,  ihave problem with my wd external hard drive 500 gb caapcity. it start not to recognized what ever computer im using. a nottice is pop up whenever i plug the device. previously it really very nice. can u help  me what should i do. i stored all of my file in the device and i want it to retriveve immediately because i have projct to finish

Appreciate your response

thank you

Joeper