In the late 1980s, a dispute arose between System Enhancement Associates (SEA), maker of the ARC program, and PKWARE.
After the lawsuit, PKWARE released one last version of its PKARC and PKXARC utilities under the new names "PKPAK" and "PKUNPAK", and from then on concentrated on developing the separate programs PKZIP and PKUNZIP, which were based on new and different file compression techniques.