Thanks for your answer. Formatting the Harddrive did the trick and now it works :) The only problem now is, that I want my macbook to connect automatically upon start up, but I can't manage to get it...

Model : Hardware Version : Firmware Version : ISP : Hi. I have a TP Link Archer C2 router, and tried to plug my external hard drive (WD 250gb) in the usb. I looks like the router finds the hard...