@Pip_12_mn --
A CO resident who has NY-source income must file both a non-resident NY tax return reporting the income earned in NY, and a resident CO return reporting ALL his income, including the income from NY.
In that situation, CO will grant an "other state credit" for the taxes paid to NY, so as to prevent double taxation. TurboTax calculates and applies this credit, but the program can only do so if the non-resident state return is completed first, so that the program "knows" the correct amount of the credit.
That's why the sequence is important.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
