I have added Solver through add-ins. Office 365, home lap top, Windows 10. Any attempt to run it produces a message along the lines of "Cannot run the macro SOLVER.XLAM!MainEx" or a variety of other SOLVER.XLAM macros. I have followed many threads addressing this issue including completely re-installing Office but nothing works. There seem to be multiple suggestions in the community as what to do, with no definitive single solution. I have used Solver for over 20 years - it is important to my research but going to Windows 10 has stopped me in my tracks for over a year now.