Doing my 2018 taxes. Everything pretty much the same except the program is ignoring my itemized mortgage interest and substituting the standard deduction. Any idea why?

[CynthiaR]

One of the biggest changes the new tax law brings is a near doubling of the standard deduction to $12,000 on single returns, $18,000 for head-of-household filers and $24,000 on joint returns ... up from $6,350, $9,350 and $12,700 in 2017. Individuals age 65 or older and blind people continue to get an additional standard deduction of $1,300 more per person ($1,600 if unmarried).

Your standard deduction is higher than your itemized deductions so TurboTax switched to the standard deduction for the marital status you are in to get you a better refund or to reduce the tax you owe.