I have a M&P Shield 9 that I can't get the slide off.

I bought it in February, and have had it field stripped three times successfully. Yesterday, the slide would only go 1/8" forward before hitting something that stopped it.

I tried about ten times with the same result. I also tried three times to pull the trigger instead of moving the Sear Deactivation Lever down. I have another Shield 9, and it breaks down with no problem at all.

I found a thread with the same name from November 2015: M&P Shield 9mm - Can't remove slide . The OP describes my issue exactly. He said it had to do with a defective Takedown Lever Retaining Wire/Spring.

I tried moving the spring around with a small screwdriver, and it jammed with the slide open. Now it won't close.

I guess it's going to take a trip to S&W, unless someone has a trick I didn't find in my search.

The good news - Now I know why I had a "spare" Shield.