I thought I'd give a final update on my situation. I waited for a few weeks and tried again to submit my mothers (surviving spose) return via Turbotax and was again rejected by the feds and subsequently by the state, since an accepted federal return is a prerequisite. I didn't want to mail them so, like many others, I spent several hours resubmitting in FreeTaxUSA. Both state and federal returns were quickly accepted.
I called Turbotax support to report my difficulties and ask for a refund of the $25 state filing fee. After some initial resistance, and a complete denial that there was even an issue, they finally agreed to refund my filing fee.
The problem is obviously not an incorrectly entered AGI since FreeTaxUSA canm handle it. I can accept that software can have glitches but I don't understand why Turbotax is burning goodwill with longtime customers by denying the problem and resisting efforts to obtain refunds.
