After almost one year waiting, I got the following email from USCIS. I have not received the letter yet but this got me very worried. Anybody knows what they want. I thought I485 should be an easy process (except for waiting). My I-140 (NIW) was approved also with RFE. Thanks!
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Application Type: I485 , Application to Register Permanent Residence or to Adjust Status
Current Status:
On February 17, 2005, we mailed a notice requesting additional evidence or information in this case. The notice explains in detail what additional material is needed. If you have questions about the notice, what is required, or if 14 days have passed and you have not received the notice, please call the National Customer Service Center at (800) 375-5283.
If you have questions or concerns about your application or the case status results listed above, or if you have not received a decision or advice from USCIS within the projected processing time frame*, please contact the National Customer Service Center.
National Customer Service Center (800) 375-5283.
*The projected processing time frame can be found on the receipt notice that you received from the USCIS.
*** Please do not respond to this e-mail message.