Get your taxes done using TurboTax

@pablomarchant  I too tried that method, and got the same results. What I ended up doing that was *somewhat* easier is to go through the main step-by-step process (not the exact titles, but hopefully it gets the point across: Wages->Investments->Broker), and then scroll down looking for each negative #. Edit that and click "Back" vs "Next", since Back saves the info.

 

I still have ridiculously long loading times, and the program goes through "Not Responding" messages after basically every adjustment made.

 

And as a reference, I had 186 of these errors, out of about 2500 trades.

Hope this helps.