Validate did not discover topology errors

Description

Validate of a Topology finishes quickly, and no topology errors are discovered where errors actually exist.

Cause

This can be due to issues such as:
- There is a feature in the Topology that contains a NULL subtype value. NULL subtypes are not supported by the Geodatabase.
- The data is in an ArcSDE Geodatabase, and one of the feature classes participating in the Topology is in load-only mode.

Solution or Workaround

• At ArcGIS 8.3, features with NULL subtype values cause problems during Validate. With Service Pack 3 installed, Validate fails with an error message identifying the feature with a NULL subtype value.
• Determine which feature class is in load-only mode and change it to Normal I/O mode. With Service Pack 3 installed, Validate fails and identifies which layer is in load-only mode.