Thank you NayaSadak for your advice. I am going to send the required details back to them soon. I haven't been here for 5 years so I guess I need to revert to 1040NR again. I thought it was okay to file taxes through Turbo-tax but once i got this letter from the IRS I don't think I want to take any chances.It was tempting to do it through Turbotax since I got double the refund than if I would done it using 1040 NR. As for CRP( Certificate of Rent Paid), what happens is with the rent that you pay your rental company, they add 19% property tax ( which is included in the rent). This percentage is refunded to you when you file form M1PR sometime during the month of August, which in my case was almost $500. Due to the fact that I filed 1040 and I am thinking the IRS sees me as NR Alien ( i guess they checked my SSN), they could found discrepancy ( which I am unsure of because I triple checked everything on the M1PR form before I sent/mailed it in) in the MRP1 form. Anybody have clues on that??