Why is asking me to post a SSN for a disabled dependent when I don’t have a dependent

I believe you may have identified a dependent as disabled - you should check the dependents section under Personal Info.  It should say No Dependents - if the contents of the Dependents section does not agree with your situation, you should edit the contents to ensure they are correct.  If it says No Dependents you may want to exit TurboTax and reenter your return to see if the error message has disappeared.  If this does not work, try rebooting your computer.  Good luck

You apparently entered on Turbo Tax that you have a disabled dependent.  You need to review the Personal Info tab again, very first tab.