ERROR 105:
Cannot open ODE solver.
Error 105 : The system could not open its Ordinary Differential Equation solver.
1. Description
GeoSWMM uses the EPA SWMM computational engine to perform hydrologic and hydraulic simulations. When you run a model in GeoSWMM, the model information is transferred to the EPA SWMM engine, which performs the numerical calculations and returns the simulation results to GeoSWMM.
Error 105 is generated when the EPA SWMM engine cannot open or initialize its internal Ordinary Differential Equation (ODE) solver. Because this solver is required before hydraulic and hydrologic calculations can begin, the simulation stops and no results are produced.
Although the error appears while working in GeoSWMM, it does not necessarily indicate a problem with a specific GeoSWMM layer, subcatchment, node, conduit, or other model object. It is primarily an EPA SWMM engine-startup error that may be related to the software environment, system resources, file access, or the affected model.
2. Technical Background
Before beginning a simulation, the EPA SWMM engine must allocate memory and initialize the data structures required by its numerical solvers.
The ODE solver supports the time-dependent calculations used to simulate changes in runoff, flow, water depth, storage, and other hydraulic and hydrologic conditions throughout the drainage system.
Error 105 occurs during this initialization stage, before the model simulation can proceed. Because the message does not identify a specific model object, begin with broad checks of installation, file access, security settings, and system resources before investigating individual GeoSWMM model components.
3. Possible Causes
Error 105 identifies a failure to open the EPA SWMM ODE solver but does not specify the exact underlying cause. The following conditions should be investigated.
- Incomplete or incompatible installation: Missing, damaged, improperly installed, or incompatible GeoSWMM and EPA SWMM engine components may prevent the solver from starting correctly. This condition may occur after an incomplete software installation, update, or manual replacement of program or engine files.
- Restricted file, folder, or security access: Windows permissions, read-only folders, antivirus software, endpoint protection, or organizational security policies may prevent GeoSWMM or the EPA SWMM engine from accessing required files or creating temporary workspace files. Inaccessible Windows TEMP or TMP folders may also interfere with solver initialization.
- Insufficient system resources: Limited available RAM, inadequate temporary-disk space, or heavy use of system resources by other applications may prevent the EPA SWMM engine from allocating the resources required to initialize the solver.
- Project-specific initialization issues: If other GeoSWMM models run successfully, the affected project may contain inaccessible external files, unusual file paths, restricted project folders, or model conditions that expose system-resource or file-access limitations.
Table 1 : Troubleshooting steps
Step | Action | Why It Helps |
|---|---|---|
1 | Confirm the error in the Status Report
| It confirms whether Error 105 is the primary simulation failure or a result of an earlier reported problem. |
2 | Run a known-good GeoSWMM model
| It separates software-environment problems from project-specific conditions. |
3 | Verify the GeoSWMM installation and source
| It ensures that the GeoSWMM application and the underlying EPA SWMM engine components are present, compatible, and properly installed. |
4 | Check project location and folder access settings
| It eliminates problems related to restricted folders, long file paths, network access, file synchronization, or unavailable temporary storage. |
5 | Review antivirus and security settings
| Security controls may prevent the EPA SWMM engine from loading required components or creating temporary files during solver startup. |
6 | Release system resources
| It frees memory and temporary storage that may be required to initialize the EPA SWMM solver. |
7 | Evaluate the affected GeoSWMM model If the known-good model runs successfully but the affected model does not:
| It determines whether the initialization failure is associated with the affected project rather than the GeoSWMM installation or EPA SWMM engine environment. |
8 | Verify the solution After making the corrective changes:
| It confirms that the corrective action resolved the EPA SWMM solver-initialization problem before further model development or analysis continues. |
✓ Diagnostic Tip
If ERROR 105 occurs when opening or running every project, including the sample models supplied with EPA SWMM, the problem is likely related to the EPA SWMM installation or the Windows environment. If the error occurs only for one project, compare it with a known-good model to determine whether the issue is project-specific before reinstalling the software.
5. When to Contact Utilian Support
Contact Utilian Support at support@utilian.com if Error 105 continues after completing the recommended troubleshooting steps.
When contacting support, include:
- Your GeoSWMM version
- Your ArcGIS Pro version
- Your Windows version
- The GeoSWMM simulation Status Report
- Whether the error occurs with all models or only one project
- Whether a GeoSWMM sample model runs successfully
- A description of any recent software updates or installation changes
Providing this information will help the support team determine whether the issue is related to the GeoSWMM installation, the EPA SWMM engine environment, or the affected model.