If you are using the Evolutionary Solver, this message appears when (i) the Solver has explored the maximum number of subproblems allowed in the Max Subprob­lems option field on the Engine tab of the Solver Task Pane and (ii) you clicked the Stop button when the Solver displayed the Show Trial Solution dialog. You may increase the value for the Max Subproblems option, or click on the Continue button instead of the Stop button in the Show Trial Solution dialog to continue the solution process.

If you are using one of the other Solver engines on a problem with integer con­straints, this message appears when (i) the Solver has explored the maximum number of integer subproblems (each one is a “regular” Solver problem with additional bounds on the variables) allowed in the Max Subproblems option field on the Engine tab of the Solver Task Pane and (ii) you clicked on the Stop button when the Solver displayed the Show Trial Solution dialog.  You may increase the value for Max Subproblems, or click on the Continue button instead of the Stop button in the Show Trial Solution dialog.  But you should also consider whether the problem is formulated correctly, and whether you can add constraints to “tighten” the formula­tion.  If you are using the LP/Quadratic Solver in Analytic Solver Comprehensive or Analytic Solver Optimization, try activating more Cuts and Heuristics in the Integer section on the Task Pane Engine tab.