I'm having the same problem. Maybe I don't understand what you mean by the word "save." When I start this program on my Windows 10 (by double-clicking on the Digital Logic Sim.exe file, since there doesn't seem to be an installer for this program), I see a dialog box with options that include creating a new project or opening an existing project. When I start a new project by giving it a name like "A New Hope," I see your screen where I can put inputs, chips, and wires. After I do some work there and I want to save the project, I get a dialog box that tells me to save it as a chip, not a project. I see the new chip. If I close the program again and reload "A New Hope," I don't see the work I was doing there. I do see the chip that was saved as "A New Hope," but that's not a project. It's a chip, and I can't continue the work I was doing in it. What am I doing wrong?