What do I do if I had one car during the first part of the year that I owned, then leased a new car in August? Every time I try to add a second car it deletes the other.
Thanks for stopping by the QuickBooks Community. I'd love to be able to give you some better news, but at the moment, this feature isn't available. In order to support multiple vehicles, the connection between QuickBooks and TurboTax would need to be configured in such a way that we would allow for multiple sets of mileage data to be transferred over. That isn't possible right now, but our team is actively looking for solutions.
As soon as there are any updates on this, they'll be posted here.
In the meantime, I suggest manually adding mileage deductions for each vehicle in your account. You can check the following articles for more details on that process.