How to efile Illinois state taxes?

[Mike9241]

you have to e-file the Federal in order to be able to e-file any state. make sure when you get to the dialog box for transmitting your return you select e-file for Illinois. when you transmit your return both federal and state will be e-filed. if you already e-filed your federal you can e-file the state but you must select to mail in the federal return. then efile state and finally, you'll be able to e-file Illinois for which there is a fee. 

[Cedro1]

I have a different situation. I was a full time resident of Illinois for 38 years, and for last few months of last year ('22) I moved to Tennessee. TurboTax gives me part time resident of IL and part time resident of TN. Additonally, while in IL, I was working in NY (filed non-resident state in NY). 
The TurboTax tells me that I can not e-file for IL, and instead must mail-file for IL state. Federal, NY, will be e-filed. It kind of does not make sense why IL or TurboTax requires to mail tax documents for IL ??!!
TurboTax states "Part-Year Returns with Credit for Tax Paid to Other States (Schedule-CR) are ineligible for electronic filing." 

[AmyC]

Part year returns with a credit for another state can usually be e-filed. IL only allows resident filers on their state website.

IL will check the non-resident credit on your part-year return. It will need to be mailed in this year due to your change in situation.

I recommend you mail it with tracking to ensure the safe arrival. Be sure to include the NY return behind the IL return.