You didn't say whether you are using TurboTax Online or the CD/Download TurboTax software. It sounds like you might be using TurboTax Online, which has a limit of about 1,500 transactions from a single brokerage. You could try switching to the CD/Download software, which can import about 2,000 transactions from one brokerage. As an alternative, instead of importing all the transactions, you could make summary entries in TurboTax, then mail a copy of your brokerage statement to the IRS. See the following FAQ for more information.
How do I enter a large number of stock transactions in TurboTax Online?
