@alvin4 wrote:
I've read I have to pay that gain regardless of whether or not I've taken the deduction in the past (I haven't)
That is correct.
In TurboTax, if you took less depreciation than you should have (including not taking any at all), you enter the amount you SHOULD have taken (which is likely the number that TurboTax auto-calculated).
If you never claimed depreciation and have filed two or more years of tax returns without that depreciation, you should consider going to a tax professional to file a form to 'catch up' on the missed depreciation that you never took.
