Based on the circumstances you describe about your particular situation, it is a reasonable conclusion that you never "abandoned" your North Carolina "domicile" (residency), in favor of California, under the tax laws, because you still retained significant ties to North Carolina, and did not firmly establish roots in California, sufficient at least to overcome the presumption that you are still a North Carolina resident.
Thus, we would recommend that you file your state tax returns as follows: North Carolina (as a full-year resident) and California (as a nonresident). This will mean reporting your California wage income on both California and a North Carolina tax returns, thus resulting in double-taxation by the states on the same wage income. But, you can then also claim a counter-acting state tax credit for taxes paid to California, such that in the end you'll only be taxed by just one state. TurboTax will do all the math for you.
Mechanically, in TurboTax, in the Personal Information section at the beginning, you will tell the program that you did not live in another state (making you a full-year North Carolina resident), but you will also indicate that you made money in another state: California. When done correctly your summary information should look similar to the screen-capture image files attached to the bottom of this answer (simply click the picture to open).
After you complete your federal tax return, you will begin your state tax preparation. The ordering of your state tax returns is important, for the state tax credits to flow through TurboTax properly. You will want to do your California nonresident return first, and then your North Carolina resident return second. When it is done in the right way, you will receive a credit on your North Carolina return for taxes paid to California on your wage income (this sequence was additionally verified by performing a hypothetical "test run" through the software, with your given scenario -- everything worked as expected).
For the next tax year, if your situation is substantially the same: a North Carolina resident working in California for some portion of the year, you should continue to file your state tax returns in the same way.
If you have further
questions, encounter any difficulties, or just want to speak with a live tax
expert who can walk you through your TurboTax entries (including the ability to
screen-share with your computer), please feel free to contact us. We
would be happy to help you (and as a paying customer, the call is free to
you). Here is a link where you can create a support ticket and reach us:
https://support.turbotax.intuit.com/contact/
Thank you for asking this question.
