Deductions & credits

You have been so helpful! Quick question, any maybe it's just an issue with the system. When I enter all the information for the home sale, it asks me if we have used a portion of the home as a home office during the time we lived there. I select yes, because that is true. It then asks me for the Depreciation and the AMT Depreciation. 

When I enter any data there, it tells me that I have to pay capital gains tax on the dollar amount entered even though the sale did not earn us $500,000. Why is that? 

I tried to determine the amount there I should enter on my own but that is what brought me to this forum! 

I just want to be certain that I don't need to enter anything there or report the sale at all and therefore pay no additional tax even though TurboTax is prompting me to do so. 

I sincerely appreciate your help!!