Fed MFJ, Taxpayer 100% NY, Spouse 100% IL

[Pythagoras]

Ugh.  Fed MFJ saves $4K+ over MFS.  Taxpayer 100% NY resident and income.  Spouse 100% IL resident and income (separated, but not yet divorced).  Chasing my tail on NY/IL state filings; both law and ProSeries procedures.  Thanks in advance for any insights.

[Skylane]

File states as MFS, if you already separated the joint returns into separate returns it should be pretty straightforward. NY is independent so shouldn’t be an issue. Not sure about IL but source income is source income
Edit; NJ allows the individuals to file as single.... not sure about NY or iL but it should be in the instructions 

[Pythagoras]

Skylane, thank you , that is helpful.  My frustration is trying to find an authoritative source that Fed MFJ is allowed to file MFS in either NY or IL.  Already spent too much time chasing this through the NY/IL websites.  If I can document that it's legally permissible, your recommended ProSeries procedure seems spot on. Thanks again for your response.