External hard drive not working, using Y-cable

My external hard drive isn't working properly. It sometimes disconnects randomly, even while using a Y-cable (I tried the front and rear USB ports). I was able to copy all of my game data to it, but when I tried copying the game data from the hard drive back to my Wii U I received this message:

"An error occurred while moving the game data. Some content couldn't be transferred."

So now some of my game data is stuck on the hard drive.

the y cable trick is not on nintendos website....it says to have a hdd with an ac adapter.

http://en-americas-support.nintendo.com/app/answers/detail/a_id/1359/p/431

try calling nintendo.

Well if it is copying it, doesn't that mean its working? What kind of external are you using? Is it a 2.0 usb external? 3.0? Its a subject I'm very curious about. I'm leaning towards making my own external.

I had similar problems when I tried using a Y-cable. Mine would format, but nothing would write. The drive itself is fine, as I'm using it for backing up my Steam games now. You're better off getting one of Nintendo's recommended hard drives, or a Sandisk Cruzer Fit(64GB). I can vouch for the Fit. I've been using one since a few months after launch.

Use a *powered* (with its own ac adapter) external HDD. Im using a WD 500GB HDD in a Welland external case that has its own ac adapter *powered*..not listed/endorse by Nintendo..but hasn't given me trouble. :P

Just put one end of the Y cable into this

http://www.amazon.com/PowerGen-Travel-Charger-Smartphone-Black/dp/B00K0D6GR8/ref=sr_1_15?ie=UTF8&qid=1418746427&sr=8-15&keywords=usb+charger

Stop trying to use non-recommended HDDs for your Wii U.

Hope you get your data off. This is why I use a Nintendo approved HD with an independent power source.

I just bought a WD Mybook external. I was going to make my own but I couldn't pass up a Nintendo approved external hdd for the price. After hearing all the horror stories about trying to find the right external I decided to avoid the headaches.

On the error screen it says you can use a Y-cable. Any hard drive should work just fine as long as you use a Y-cable (for portable drives) or an AC adaptor (for desktop drives).

I figured out the problem. I just had to disable the hard drive's sleep mode and now it works perfectly.

congrats man! lucky you didnt have to do anything bad.