If your slide got stuck, you have to give it a hard smack to dislodge the slide from the grip safety. Which is usually the last thing I want to be doing with any firearm. But, that's what my guy at the gun shop did to get it loose when showing me a demo model.
The same thing will happen when putting the slide back ON, if you depress the grip safety. Not just taking it off.
A customer just brought his into my shop. He bought the pistol (EZ 2.0 9mm, no thumb safety) new from me last week. He has an original EZ-380 so he was familiar with the platform. During reassembly it locked up on him. When he brought it to me his slide was still forward about 1/8", the slide lock swung down, and the slide would just wiggle front to back about 1/16" or less. While wiggling the slide I saw the grip safety moving a little too. He thought he remembered he had pulled the trigger while the gun was apart. Don't do that.
He had done some internet searching before he came in and directed me to this forum. I'm glad he did. Since this was a brand new gun he didn't want to do something to tear it up. I can understand that. I diagnosed and got his gun right again and he was away in about 2 minutes. After he left I signed up with the forum and replied to this thread to give a little more information to anyone else that may run across this with their EZ's in the future.
I can confirm this "solution". Take a small piece of wood or something else that won't scratch the gun, and give the back of the slide a couple of raps, in parallel direction with the barrel. I used a 32oz. ball peen hammer handle. I gripped the hammer head and went in-line with the slide. More of a push than a swing. You don't have to SMACK it, just firm little love taps. Start light, then get progressively more firm until the slide moves forward. If it just ain't happening don't wail on it. There may be a different problem then.
From what I observed, tapping the back of the slide jars the grip safety bar linkage enough to get the slide to jump past it. Then you can remove the slide, put it back on, pull the slide back and lock it open, swing the slide lock bar back into place, and you're done.
Yes, avoid the grip safety during disassembly and reassembly. After I got his gun running again I could replicate the problem by pressing the grip safety during reassembly. Giving a couple more little taps/pushes and it was free again. I did this to show him what to avoid, and what to do if/when it happens again. S&W does have some room for improvement with the grip safety linkage geometry that can resolve this issue. Maybe in the 3.0 EZ. Even though it doesn't hurt anything you shouldn't have to fight a new pistol apart or have it lock up on you this easily during reassembly. I'll pass this info along to S&W to at least make them aware. These are excellent pistols, even with this one annoying little flaw.