Glass break sensor won't open!

Yes just push up and might have to put some force into it 

I have the same exact problem.  Pushed like hell and nothing.  What the heck? 

Thank you for that info.  I found out the problem with mine.  Turns out the mounting bracket is very, only maybe a sixteenth of an inch.  Mine is mounted to the ceiling.  So I could not even see the mounting bracket.  The only way to see the bracket is if you slide the device out of it.  The deceiving part is that the front cover looks like it is the part that comes off, but it is not.  Thank you for the info on which direction to push.  It will definitely come off in only one direction and the idiotic video they have of how to replace the battery does not show you which direction that is.  So I ended up having to rip mine off the ceiling, and once I did that, I was able to see how the thing came apart.  Thanks.

Same problem! Mine was never adhered to the wall. Can’t imagine trying to remove cover when device stuck to wall!

Can’t open it either. Ridiculous!

At the top of the sensor (find the small button) there is a tab at the back. Press the tab and the sensor cover comes right off.  However, this only worked for me because the sensor was not flush mounted against the wall.

What an effing POS.  There is ZERO way to get these things open once mounted on the wall. I had to rip mine off the wall thereby destroying the drywall. Then get a putty knife and force the edge of it into the miniscule slit space on the back of the sensor at the top (end with the button on it). Then forcibly work it up and open.  The online video is pathetically worthless. 
And I’ve got three more to do!  Or just let the damn things die rather than destroy my walls — and get rid of Simplisafe!!! 

Emily_s — above …. You should read your own supposed reply and realize how ridiculous it is. “Press down on the sensor and slide it up”.  Right.  Coz that makes total sense to push down and up at the same time. 

I didn't mount mine, they're free standing.

It's not easy to explain since they're not mounted.

If mounted; The meaning of press down, is push in on on the sensor and push the front part of the sensor up. Up is where the reset button is. Don't push too hard in, add some force up.

On my freestanding glass break, I hold the front in right hand, and put two left hand fingers in the back at the bottom cavity at the back, thumb on bottom, there is a sorta cavity on the back at the bottom.

Pushing front up slightly and pulling down in the cavity, it pops right off.

I'd take video & pics but can't hold both phone and sensor at the same time. Not my job anyhow.

With as much trouble as some folks have with this sensor, for whatever reason, it would behoove Simplisafe to take some pics and videos from various angles with proper directions.

They seem to have time & money for propaganda videos on Facebook etc.😉😁