SOS,I was selecting pics to send to my sister in Toshiba hard drive which contains everything important to me,including videos shot when I got married and pics of my family.
First I insert the hard drive into my macbook pro retina;Then I select pics I need;during this time there is always some tiny short pause which I thought was normal like always. However,it suddenly flashed and the icon on my desktop disappeared as well.So I decided to reinsert the hard drive again. It was this action that led to the error,I suppose.

My mac is as follows: version 10.11.6,2.6GHz inter Core i5, 8GB 1600MHZ DDR3. The Toshiba machine hard drive was bought several years ago, which I haven't used for almost a year.

I'm desperate now! As a Chinese guy whose English is poor, I really don't understand too much about professional English either. Hope you guys could give me some advice. You can reply me here or just send me an email 1912401908@qq.com

Yours sincerely,
Jason