Should a Federal tax refund change to Federal tax due the moment you begin the State return?

It's impossible to tell without seeing your return, but it does take a few moments sometimes for the refund meter to react to something you entered into it. Do you have an underpayment penalty?

You can preview your tax return to make sure everything is accurate. You can do this by following the instructions below.

Try previewing your actual return as it is a more accurate reflection of your refund amount or tax-due amount. 

You can get to your tax return in TurboTax desktop as follows:

1. Switch to Forms Mode, and then  (see screenshots below for additional guidance)
2. Scroll through your forms in the left panel and 
3. Click on the form you want to preview (Example Form 1040)

You can get to your Tax Return in TurboTax Online as follows: 

1. Go to "Tax Tools" in your left panel,
2. Select "Tools" and then 
3. Select "View Tax Summary" and 
4. Select "Preview Form 1040"

Click here for "How do I update and print a new W-4?"

Click here for "Why do I owe taxes?"

Click here for "Video: Why Would I Owe Federal Taxes?