May be this is the reason.
ADJUSTMENT AND NATURALIZATION CASES ON HOLD. INS confirmed with ACIP that rumorsof a halt to adjudications are not true. However, some naturalization and adjustment of status cases will encounter delays due to additional security check procedures. The new procedures require that when an FBI name check results in an indication that a record may exist (a "hit"), INS must receive a definitive response from the FBI before it can approve an adjustment of status or naturalization application. To facilitate this process, some computer system enhancements are being installed. During the installation process, adjudications will
continue but final determinations will not be issued until the upgrade is completed. This is expected to take 1-2 weeks.
