How do I enter placeholder SSN# for non-resident alien spouse? Its not letting me proceed in turbotax.

In order to finish your return in TurboTax to print out and mail, you will need to enter a "dummy" SSN for your spouse.  You can enter 999-88-9999 just to finish your return.

Then when your return is complete, you need to print your return and "white-out" the dummy SSN and enter "NRA" in the field for the SSN.

You will need to mail your return.