A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Here are videos that explain how to use solver.
https://www.youtube.com/user/ExcelIsFun/search?query=solver
I've seen no reports that Solver isn't working other than yours, which hints strongly that you are not using Solver correctly. If you can find an example in the videos that doesn't work the same on Mac as it does in the video, please reply with the video and I'll be happy to check it out.