If you do not have your spouse's social security number and are trying to file married filing separately, you will not be able to efile because the IRS requires married people filing either MFJ or MFS to provide both spouses SSN when efiling. The only way around this is to file MFS and paper file your tax return. When you are finished the Review phase of your tax return preparation, select File and choose File by Mail instead of Efile. Then you will print, sign, date and mail in your tax return.
