Symptom

Running the Subnetwork generator leads to an error message:
"Number of rows .. of demand segment .. exceeds maximum 2147483647. Functions based on individual routes, such as the route list and subnetwork generator, are not available. Bush-based functions, such as flow bundle, OD pair filter, and TFlowFuzzy, however, are still available. To limit the number of routes, use an OD pair filter or flow bundle."
 

Cause

The subnetwork generator cannot process this number of routes available in this model, it is not possible to create any subnetwork including routes.

Workaround

Create a subnetwork without routes, by initializing the assignment: Calculate -> Initialize assignment
When relying on the creation of subnetworks, consider to use an assignment method producing less routes.