stuck shark model NV 450 26 vacuum dust cup unlock button stuck

"My Shark model NV 450 26 dust cup unlock button stopped working – I can’t remove my dust cup." 

My shark model NV 450 26 dust vacuum has been idle for a while. It used to be easy to use, we press the dust cup release button, the dust container will be lifted up easily. This time, we press the button, the dust container stucks. We have tried to pull it up hard, the rubber is almost bent and about broken, but nothing works. Maybe the button is broken.

I googled and found the above question in a forum, but there is no reply. I also tried to search image and understand how the button works, there were a few blur images. I also searched the manual, no solution, no image of the button or how it works. The amazon product don't explain it neither. The ebay has a few posts with parts image. I saw the image of the dust cup unlock button and believe it is too dumb to be broken.

Not sure why it is so hard to find information online for such a simple thing.

With that confidence about the button, we figure out the following way of unstuck the dust cup unlock button with some try error:

Have one person press that button, another person pull the dust cup sideward, (don't pull the dust cup upward), the dust container easily popped out. 

Since I can not reply that "My Shark model NV 450 26 dust cup unlock button stopped working – I can’t remove my dust cup." on the original website, I decided to post the solution here.

I spent time searching it, so I post it, hope it helps. 

By the way, after pulling the dust container off, it turns out the dust cup unlock button is very simple and robust.

Look at the images.

When the button is up, a latch hold the container in place. 

Once the button is down, the latch is pressed down as well, no longer holds the container.

At this point, the container is free to move sideward. If the vacuum is not used for a long time, grease etc. will glue it in place, you need some force to move it. 

Trying to pull it upward won't work, the dust container is not able to move upward before moving sideward first. That is what got us at the beginning.