If you did not use TurboTax in prior years and are adding an existing rental property, TurboTax will calculate the accumulated depreciation that should have been taken, based on the information you input (cost basis, date placed in service, etc.). If the amount the program calculates is different than your actual accumulated depreciation you can the amount TurboTax calculated by editing the Asset Worksheet. You can only do this if you are using TurboTax Desktop (which I highly recommend if you have rental property).