Always take what Intuit Support tells you with a pinch of salt. OK, I exaggerated. I meant a spoonful of salt!
It wouldn't be the first time they try to put the ball back in your court if they can't figure things out or don't understand the problem. That's why this Community is such a great resource - most of the time, people do get quick useful answers here.
Now, back to your problem. You definitely shouldn't have to paper file. SIT should flow, period. The Electronic Filing (W-2 State/Local) entries I mentioned in the earlier post won't even affect how SIT flows, just that those entries are essential for e-filing. All it takes for IL SIT to flow from the W-2 input is to code it to IL. Here's what I have on a sample return.
If you could post your screenshots (but make sure you redact any sensitive info), we may be able to identify what the cause is. Please also let us know the following -
1) Whether IL is a resident, part-year, or nonresident return; and
2) What you have entered on General > Client Information, under the Resident Status section of the input screen.
