I put 0 in QEF W2 Box 2 for federal tax withheld and get an error message saying it "must be less than zero". In case it matters, the wages in Box 1are 0 because all the salary was contributed to a 401k (reflected in Box 12 (D)).
If I change it to -1 (impossible, I know), it says "shouldn't be less than zero".
If I change it to 1, it again says "must be less than zero".
Sooo, I can't complete the form and file the W2.