Symptoms

While trying to delete a custom batch type in the project on the ABBYY FlexiCapture 12 Application Server, the error occurs:
Violation of PRIMARY KEY constraint 'PK__#<some number>'. Cannot insert duplicate key in object 'dbo.@processingStageMap'. The duplicate key value is (<some number>). in method { call BatchType_Delete(?) }

Cause

This custom batch type has script stage/s in the workflow.

Resolution

Delete script stage/s from the workflow, and after that delete the batch type.