Appendix A — Common errors
A troubleshooting checklist — the classic stumbling blocks (we have tripped over several of them ourselves):
| Symptom | Likely cause | Solution |
|---|---|---|
The .exe “does nothing” and closes without any message |
Cygwin binary without cygwin1.dll (silent error 0xC0000135) |
Compile from source with -static (see the compilation chapter) |
Grid mismatch in TopoIndex or TRIGRS |
Grids with a different number/position of nodata cells (clipped from different sources) | Clip everything with the same mask and check with gridmatch.exe |
| Results do not appear | The output folder set in tr_in.txt does not exist |
Create the folder before running |
| FS = 10 everywhere | Normal behavior: FS is capped at 10 in stable/flat cells | Focus on the cells with FS < 1.2 |
| Absurd FS or pore-pressure values | Wrong units — rainfall in mm/h instead of m/s is the classic one | Review the units section |
| Error reading a grid | .asc file with a comma as decimal separator (Windows/Excel regional settings) |
Make sure the .asc files use a decimal point |
| TopoIndex hangs or gives strange results | Wrong D8 scheme (ESRI = 1 vs TopoIndex = 2) in tpx_in.txt |
Use 1 for flow-direction grids generated in ArcGIS/QGIS (ESRI scheme) |