So I had this issue a while back and it has only just re occurred as I need my external hard drive again. So I use this drive throughout the week and have done this past week and all seemed to be fine, however today I plugged my WD External hard drive in to my Mac Air and it does not show up, even though this light is blinking indicating it is working? I also looked at a few other suggestion and decided to repair the disk due to it being greyed out on disk utility, no luck. Any ideas, I cant afford to wipe it either, Ive got so much on this stupid hard drive, and i have solved this problem in the past? Thanks.