Friend, brand new Shield 9mm 2.0 With Safety.

Slide lock, mag out, UNABLE to depress slide release.  220# strong guys.  Broke fingernails trying.

Slide taken off.  Looked. Nothing wrong or unusual. Catch moves freely with out or with slide.  

Just refuses to exit notch in slide.

Common?

Advice.

Are you sure it's a release?  Some are not.  I can't remember if it's my Shield or my XD that's just a lock, and not a release.   Anyway,  I got in the habit of just pulling back on the slide and letting it go to release it.  It works on all of them.

Mine was the same.  Polishing helped some.  Noticeably better after 500 rounds.  After 1k, feels pretty normal.

It is not designed as a slide release on the shield. It’s designed as a slide lock only. Rack the slide to load.

Yeah, it's technically a slide lock, not release.   Have to manually slingshot it for a while and loosen it.

EXACTLY THIS!

Which was really confusing considering the Gen I M&P would let the slide slam home without touching the Slide stop / Slide release if just you slammed a fresh magazine into it.

One would not release no matter how hard I tried, and the other would release without even touching it.  Extremes!!

Spent a lot of time in front of the TV, just working the slide release back and forth and back and forth and now it has worn in, but Stiff Slide Lock / Slide Release it is a VERY common thing.

Very Stout Recoil Spring & Deep Cut for the Notch make for some "Maximum Effort' needed, especially when new out of the box.

BIGGER_HAMMER

My 2.0 FS M&P was much the same.  Took right thumb and left thumb to force the slide release down.

After a few months of using it I find I can right thumb it down just like my 1.0's.

My dad used to say, "If the guys who designed these things had to use them, we'd all be better off."

My 5" 2.0 is stiff enough that I can't release it with my thumb, but my 4" can. Either way, I just release it by grabbing the slide.