How do I fix the error ‘Sales Price: field integrity exception: UnitPrice (only one of unit price or total price may be specified)’ when cloning an opportunity?

There is a restriction that only the Unit Price or Total Price is present when creating an Opportunity or Quote line. The default clone configuration action for all fields is to clone them, so one of the field’s configuration actions must be set to clear the value.

Try setting the configuration action for the Total Price(totalprice) field as ‘Leave Empty’, and leave the Unit Price(unitprice) configuration action as ‘Clone’.