Dictionary override conflict: field definition conflicts with base system

A custom dictionary override was created to modify a base system field, but the upgrade changed the base field definition in a way that conflicts with the override attributes like type, length, or constraints. (high likelihood)

The field's data type was changed in the base system during upgrade while a dictionary override maintains the old data type, creating an incompatible configuration. (high likelihood)

Field constraints such as mandatory settings, default values, or choice lists were modified in the base system but the dictionary override still enforces the previous constraints. (medium likelihood)

The base system field was deprecated or removed in the upgrade while a dictionary override still references and attempts to modify the non-existent field definition. (medium likelihood)

Multiple dictionary overrides exist for the same field across different scopes, creating conflicting definitions that become apparent during the upgrade validation process. (low likelihood)

Step 1: Navigate to System Definition > Dictionary and search for the conflicting field name mentioned in the error to identify all dictionary entries and overrides.

Step 2: Compare the dictionary override attributes with the base system field definition by checking both the custom override record and the out-of-box definition to identify specific conflicts.

Step 3: Review the upgrade documentation or release notes for the specific ServiceNow version to understand what changes were made to the base field definition.

Step 4: Determine if the dictionary override is still necessary by evaluating whether the business requirements that prompted the original override are still valid or have been addressed by the base system changes.

Step 5: If the override is no longer needed, delete the dictionary override record to allow the base system definition to take precedence.

Step 6: If the override is still required, modify the dictionary override to align with the new base system field attributes while maintaining the necessary customizations.

Step 7: Test the field functionality in a sub-production instance to ensure the resolution works correctly and doesn't break existing functionality or integrations.

Step 8: Clear the dictionary cache by navigating to System Definition > Cache and selecting Dictionary, then monitor the System Log to confirm the conflict is resolved.