You are correct that your entry of 240 square feet for the Simplified Home Office deduction should not cause an error on Form 8829.
You could Delete Form 8829 from your return, then re-populate it by going through the Home Office section in TurboTax again.
How to Delete a Form:
https://ttlc.intuit.com/replies/3288508
**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"
