<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi John,<div class=""><br class=""></div><div class="">I tested Cbc 2.9.2 on OS X with the attached free mps file and found the same issue for this maximisation problem:</div><div class=""><br class=""></div><div class=""><i class="">Coin0505I Presolved problem not optimal, resolve after postsolve<br class="">Cgl0013I Postprocessed model is infeasible - possible tolerance issue - try without preprocessing<br class="">7 relaxed row infeasibilities - summing to 1604<br class="">7 relaxed row infeasibilities - summing to 1604<br class="">7 relaxed row infeasibilities - summing to 1604<br class=""><br class="">Result - Optimal solution found<br class=""><br class="">Objective value: 56640.00000000<br class="">Enumerated nodes: 0</i><br class=""><br class=""></div><div class="">It is shown that an optimal solution was found ... but as for the example I sent Yesterday .... one of the non-negative variables (x[1,1]) is shown in the solution file with a negative value. </div><div class="">Without preprocessing the problem is stated as infeasible.</div><div class=""><br class=""></div><div class="">Thanks,</div><div class=""><br class=""></div><div class="">Mike</div><div class=""></div></body></html>