Did you import a Form 1099-B from one or more brokerages? Did you have other investment activity such as stock sales?
Check the message that you received. Did it say Schedule B, or Form 1099-B? Forms 1099-B from brokerages are typically where large numbers of entries come from.
Check your Schedule D. That may be where the rest of your entries are.
TurboTax is equipped to handle around 10,000 individual transactions per brokerage account. If you hit the transaction import limit, you can enter a summary for each sales category which can reduce the number of entries needed. See this help article for more information.
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"