You cannot dispose of a portion of an asset in TurboTax.
An easy solution would be to delete the asset and re-enter it at the cost of the machines you still have. When you report the cost and date purchased, TurboTax will calculate the proper depreciation for the current and prior years.
Then, enter the one you sold for the rest of the original cost of the ten machines you purchased, then report the sale of it.
It would be better if you entered each machine separately, then the next time you sell one you won't have this problem!
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