Agree. You cannot e-file a tax return using TurboTax if your spouse is a nonresident alien and does not have either a Social Security number or an ITIN issued by the IRS. You will have to file as Married Filing Separately.
When completing your tax return and the TurboTax program asks for the spouse's Social Security number enter 999-88-9999. After completing the tax return you will have print the return for mailing. On the printed Form 1040 erase the Social Security number for your spouse and write in NRA.
See this TurboTax support FAQ for printing a tax return for mailing when using the online editions - https://ttlc.intuit.com/turbotax-support/en-us/help-article/printers-printing/print-mail-return-turb...
However, if you decide to file your tax return as Married Filing Jointly you must apply for an ITIN with the tax return and you would need to be providing a statement with your tax return that you want your Nonresident Alien Spouse Treated as a Resident. See IRS Publication 54 Tax Guide for U.S. Citizens and Resident Aliens Abroad page 7 - https://www.irs.gov/pub/irs-pdf/p54.pdf
Go to this IRS website for ITIN information - https://www.irs.gov/individuals/international-taxpayers/general-itin-information
