Unfortunately mine did this just before it died. I was able to continue using it by cleaning it out with alcohol used to clean electronics. I got some at Best Buy and unplugged the box and put some on a lint free thin rag and wiped the contacts inside as far as I could go and let it dry overnight. I got a fair amount of dust dirt out and it worked again for a while but then it died after about 6 months. I bought an amazing box and soon after had to upgrade my machine so now I don't even need a card writer so before investing in a writer box make sure there is no new machine in your near future.
Also, recently at my dealer they showed me a new wireless device that had a card that goes into the machine then when at your computer you simply send the embroidery to the card plugged into your machine wirelessly and it pops up as if read from any other card! It was the same price as the smaller writer and can connect to just about any machine so this may be more what you want to invest in so that if you do switch machines like I did you don't waste the money for a writer you may not need in the near future. With this one you could send off any embroidery to any machine with one click on your computer! TOO COOL!