7. The conditions for Assume Linear Model are not satisfied.

This message appears if you have selected the linear Simplex Solver "engine," but the Solver's numeric test to ensure that the objective and constraints were indeed linear functions of the decision variables was not satisfied. (The wording of this message may be slightly different in the enhanced Solver products, which don't use the Assume Linear Model check box.) To understand exactly what is meant by a linear model, read the topic "Solver Basics."

If you receive this message, examine the formulas for the objective (Target Cell) and constraints for nonlinear or discontinuous functions or operators applied to the decision variables or adjustable cells. You can always write a linear function using only @SUM and @SUMPRODUCT.