After my state and federal were accepted, and after all Michigan forms are available, why does my city tax forms still say "DO NOT FILE. FORMS NOT FINAL."?

Believe it or not, some forms are not available for print or mailing even if they are available for efiling.

The IRS started this tax season pretty far behind.  That kind of delay flows down to the states.  So the IRS finalizes their forms and then the states finalize their forms.  And then the TurboTax programmers get the forms and have to integrate them into the TurboTax program.  Then there is testing to make sure that the newly added forms work with the program properly.  Then they are rolled out to the public.  As inconvenient as the waiting is it will still get your tax return processed faster than paper filing it.

Here is the timeline for the release of state forms on TurboTax.