Efile state amended return

The new law that excludes up to $10,200 from taxable income will automatically be applied to your tax return already filed and a refund will be issued to you if you qualify. You don't need to amend your tax return, the refund will be processed based on the return you already filed.

The State of Missouri requires me to file an amended return, but turbo tax will not let me. How can I do this, or do I have to mail it in. Not fair. Turbo tax should be on top of this.

You should wait until your Federal return is fully processed before beginning to amend your state tax return. Most state tax returns begin with the federal adjusted gross income, so if your Federal return is being adjusted, this will affect your state amending process.