Dell C2665dnf User Manual page 497

13 Lower the operator panel back in place.
14 Reinsert the removed waste toner box.
CAUTION:
If the waste toner box does not fit into place properly, make sure that the transfer belt unit is fully inserted.
15 Turn the waste toner box lock lever 90-degrees clockwise to lock the waste toner box.
495
Maintaining Your Printer