I was having the same issue. I clicked on the forms button and found NYS form IT-196. I clicked on the Quick Zoom to Deductible Home Mortgage Interest Information. I noticed that the End of Year Mortgage Principal line was blank. I got this information from my 1098 interest statement from my mortgage lender. This seemed to take care of the issue and I was able to file my NYS taxes.
Disclaimer! I'm not sure if this was the right approach, but it seemed to work for me.
