The Debugger box on the General Solver tab:

debugsolver

gives you control over the output level and the solver used as part of the model debugging command, Solver|Debug.  The debugger is very useful in tracking down problems in models that are either infeasible or unbounded.

The Output Level option controls how much output the model debugger generates.  Possible output levels range from 1 (minimum output) to 15 (maximum output).  In general, you will want to generate as much output as possible.  The only reason to restrict the amount of output would be to speed debugging times on large models.

The default setting for the debugger output level is 15.

The Cold Start Solver and Warm Start Solver options control the solver used on linear models for cold starts (starting without an existing basis in memory) and warm starts (restarting from an existing basis) during the debugging process.  In either case, the available options are

•Solver Decides — LINGO selects the solver it believes is the most appropriate,
•Primal — the primal simplex solver will be used,
•Dual — the dual simplex solver will be used, and
•Barrier — the barrier solver will be used (requires a barrier solver license).

With some models, you may find that choosing a particular solver improves overall performance of the debugger.

LINGO defaults to Solver Decides for both the cold and warm debug solver.