USB Copy dosent work always

Hi all,
i have a questio, do you guys have problem with detecting USB connection? every time i have to unplug the reader unplug the card from reader and then pray … its doing the same thing with DS918 and DS1621. i have a pro card reader from Sony. its works fine on my computer…

I have not seen that before. Though it could be due to the fact that you are using an adapter between the card and the NAS