Why do I see Schedule K-1 for a Sole Proprietorship?

I am operating a small business as a sole proprietor (no other employees other than myself), married filing jointly. After completing my income (all 1099s for the business) and deduction information (including Schedule C deductions), upon Smart Check of Personal Taxes, I get an error for Schedule K-1, S-Corporation Name. I do not see Schedule K-1 in the forms section of my return, but it is not my intent to file as an S-Corporation.

 

Why might I be seeing a Schedule K-1 when I'm wanting to file as a Sole Proprietor?