What was wrong? Did the IRS change your return?
100% Calculation Guarantee
Turbo Tax is a self prepared return. It has no way of knowing or checking that you entered something wrong or in the wrong place or entered something twice It doesn't check against any outside sources. The IRS has copies of all the W2s and 1099s your employer and banks/brokers, etc. sent in to match against. Turbo Tax only checks the calculations of what you entered. It is your responsibility to check it over before you file. They only Guarantee that the calculations are right based on the entries you made.
Generally, no. If you purchased the desktop program to install on your own Mac or Pc, there is a 60 day no questions money back guarantee. Otherwise, TurboTax guarantees accurate calculations, and if there is a calculation error that results in a penalty or interest, TurboTax will pay that, provided you follow the notice requirements. But you always owe your own correct tax, TurboTax will not pay your tax, just the interest and penalties.
Also, TurboTax only guarantees accurate calculations based on your input. If your input is wrong (forgot income, claimed incorrect deductions, etc) TurboTax can’t take responsibility for that because TurboTax can’t read your mind or examine your financial records. It only knows what you tell it, and if you give it incorrect information, you will get an incorrect answer.