We have 2 HP8150DN that our drafting dept. prints to with no problems, anthill we added a HP4550DN. All of our PC3 files go to the HP8150DN one for 8 1/2 x 11 and the other for 11 x 17. After the HP4550DN was added to our computers all of our prints only want to print to that printer and we have to reconfigured our drawings every time we print. When the HP4550DN is uninstalled from our computers we have no problems printing. We do need both printers for the work we do. The HP 8150Dn is set as my computers default.