replying to Nosmo King, John wrote: The problem is with the "deadlatch" mechanism in the exterior door lockset, which keeps someone from jimmying the lock open from the outside by pushing on the latch which locks up the latch when the extra pin that slides along the latch itself is depressed after the door closes and latches. The Schlage locksets are known for this failure in their latch mechanism after about 5-10 years depending on frequency of that exterior door use, and your symptom is the classic one of having to turn the knob slightly to get the latch to slide on the striker plate and the door to close. Schlage has a lifetime warranty on the part and will send you a replacement latch mechanism which is the part with the latch that installs in the edge of the door. The knobs and tumbler lockset that mount on each side of the door are reused, although they must be removed before removing and installing the latch mechanism. I've got the same problem with the back door on my house, and as much as I'd like to be able to at least temporarily repair the latch mechanism while waiting on the free replacement from Schlage, it's not feasible. It became very clear on examining it that the mechanism was not designed to be disassembled without the risk of damaging or destroying it. I could have gotten it apart. I've professionally disassembled dozens of products to document how they were fabricated and assembled in the manufacturing process. The issue in doing so was the risk of not being able to reassemble it into at least a partially functioning latch. The consequence would be inability to close and latch or lock an exterior door on my house. Not an acceptable risk. Better to have a partially functioning latch that effectively locks and none at all until the latch from Schlage arrives.