MAGI for what purpose? With no traditional IRA contribution there is no need for a MAGI for the purpose of a traditional IRA contribution.
Is your spouse making an IRA contribution?
Where are you seeing a display of MAGI when you have entered no traditional IRA contribution? There are many types of MAGI, all calculated differently for different purposes.
Apparently you are using the online version, so if TurboTax is displaying a useless MAGI, I would just ignore it. Summary displays in TurboTax are frequently flawed or misleading. Because these display flaws don't affect the filed tax return, there is little incentive for Intuit to give such problems any consideration.
