How Can I Delete a Customer if they Have Orders Entered in the System?
Customer can not be deleted if they have orders (invoice, notes, etc.) associated with them.
However, a user can override this block with the purge delete feature. Clicking this button allows the user to delete the customer profile and ALL associated records such as orders, invoices and notes. If you do not see the “Delete And Purge” button, please email firstname.lastname@example.org to have it enabled.
If you want to keep these records, we suggest making the customer profile inactive rather than deleting it (see: 2 Reasons to Make a Customer Inactive)