PRT texit is negative (unexpected)

[wpbonelli]

Discussed in https://github.com/MODFLOW-ORG/modflow6/discussions/2356

^{Originally posted by p-ortega June 12, 2025} Hi all,

I updated a model (DISV) from MF6 v5 + PRT (nightly build) to the official 6.6.2 release.

When running PRT using the CBB and HDS files from a previous GWF model, I’ve noticed:

• It fails with 'texit is negative (unexpected)'. The stress period at which it fails depends on the EXIT_SOLVE_TOLERANCE with lower values causing the failure to occur later in the simulation.

Any help on what to look for would be greatly appreciated.

Pablo