Dynamics NAV - Purchasing - Overhead Applied account must have a value

This occurs when a Purchase Line has a value in the Indirect Cost % field.

This field automatically populates if the user changes the value in the Unit Cost (LCY) field.
NAV will assume that the difference between the Direct Unit Cost and the Unit Cost (LCY) field should be populated to the Indirect Cost %

To resolve this issue, clear the Indirect Cost % field on each affected line to allow the Unit Cost (LCY) field to recalculate/