Problem with reading model .mps file with a size of 3MB

[yellowdrac]

I’m running into a strange issue when solving a mixed-integer model via MPS files. Here’s my workflow:

1. In Process A: I build the model programmatically in VBNet using the Highs API (add variables, constraints, integrality flags, etc.).
2. I call h.writeModel("model.mps").
3. In Process B: I create a fresh Highs instance in a C++ code, h.readModel("model.mps"), set options (including a time limit), and h.run().

Problem:

• When I solve via the MPS file, no solution is ever found, and the solver seems to ignore the time limit (it runs until I kill it).
• If I skip the MPS step and solve the exact same model directly in Process A (with only variables/constraints), HiGHS always finds a feasible solution in under 60 seconds.
• I’ve verified that both approaches report the same getNumCols(), getNumIntegrals(), bounds, RHS, etc.
• This only happens on one particular instance whose model.mps is > 3 MB. All smaller instances work fine through MPS.

In the console log file, there is not any message or warning at all
I attach this file that was built with writeModel, I have uploaded it as .txt file beacuse github doesnt allow me to attach .mps files

model-sandbox.txt

[jajhall]

The file size doesn't affect HiGHS, so the error you're experiencing is a consequence of the VBA environment, which we don't support.