TurboTax will give you a "Warning" that says "To qualify for the Northern Resident's Deduction, you must live in a prescribed northern zone for at least six consecutive months". This is a warning only and does not mean you cannot claim the Northern Residence Deduction. You should, however, click on the Review button next to it, click Applies to Me, then check to see that you have correctly entered your dates as shown in the screenshot.