Error 4150 arises when the National Insurance number on the staff profile has an incorrect format. Click on the Error and it will take you to the staff profile. Click on the cog next the staff member's name to bring up the Personal Details page:
Where provided, the NI Number must be 9 characters, where the first 2 characters must be alphabet characters, the next 6 characters must be numeric and final character can be A, B, C, D or space.
Also, the first character must not be D,F,I,Q,U or V and second characters must not be D, F, I, O, Q, U or V.
In the example above the staff member has the first two characters set to Q, which are not valid. Also the final character is G, another invalid letter. Verify the staff member's NI Number, amend it, and then click Submit at the base of the page to save. Return to the Workforce Census area to recalculate your Census.