I sold options short and turbotax objects to the sale date being before the purchase date. How do I tell it to ignore this 'error'?

Because your opening transaction is a "sell to open," in TurboTax, on the sales information screen, you can select your opening transaction as The date this investment was acquired.  Select Options as the type of investment, and enter a description.  

You will have to select whether the option was Sold or expired?, select Sold.  Enter the date you closed the option as the Date sold or disposed and enter the amount of the premium you received in the Proceeds box.  Your cost is the amount you paid to close the option and enter that amount in Box 1e - Cost or other basis.  Select Continue and enter additional short option transactions if necessary.   

@Andrewtarkincoleman