When you use SSIS Dynamics CRM Destination for the Update operation, you may get the following error sometimes.
Exception: Entity Id must be specified for Update. ValidationPath=/0. ApiExceptionSourceKey=Api/PrePipeline
Parameter name: Target
You have not mapped Primary Key column or you have not supplied UpsertKeyField Name in the Properties Grid.
Make sure you mapped at least Primary Key Field or Map Alternate Key Field and specify its name in the UpsertKeyField property (This field indicates to CRM, which Column to use as JOIN key for lookup).