Lotus was so intent on protecting their revenue stream from software piracy that they built copy protection into the program. If the program was copied from one drive to another, it would not run. So if one bought a new computer or if the hard drive failed, the program could not be transferred to a new drive. The first versions of the software were pretty buggy too. I always visualized a Lotus company with a few programmers and many lawyers. They finally included a floppy disk that would allow a very limited number of copies, but still a PITA.