When can I submit my Missouri State Income Tax. It says my MO e-file status is INCOMPLETE

E-filing a state is only allowed once a federal return is accepted/rejected. State returns will show incomplete until federal has been accepted. If you already e-filed your federal return, you'll have to wait until your e-file is accepted/rejected in order to proceed with state.

You will have to come back (after your state forms are ready or after your federal return is accepted) to complete your state return.

When you come back to complete your state return, the following steps will allow you to file, if you have already filed your Federal return.

1. Click on Visit My Tax Timeline
2. Under Some Things You Can Do (below your 2015 return statuses), click on Amend (change) return
3. Click on Amend my return
4. Click on the File tab and go through the prompts to file your state return

My federal return was accepted but turbo tax still says I can't file my state yet. Says tax forms aren't ready yet?

There have been a lot of tax changes and the IRS and the state tax departments are still updating some forms. This is common early in the filing season.
 

Here is a link where you can select the type of TurboTax you are using and your state, to see when different forms are expected. The dates may still change and this link will be updated.  When you go through TurboTax Review, it should tell you which unavailable forms are needed in your return.
 

State Tax Forms Availability Dates