So see what's going on, the thing to do is to open Terminal. Then, copy the following to the clipboard:
Code:
sudo lsof | grep SDCopy
Paste that into Terminal. Press Return at the end of the line, then enter your password (it won't echo) and press Return.
That'll print a list of what we're copying at the time -- the last two lines are what we're reading and writing, which should help you (and us) understand what's going on.