I just had the same thing with mine, which happens when you close the door before reinserting the top. What happens is when you close the top first, there a red lever that needs to be pushed in by the lid. If you reverse this, you miss out on pushing that red tab and it ends up being a nightmare. To fix this, you need to moderately release the canister by pressing on the 1/2” lever at the bottom and moving the canister as much as you can, then, basically pry open the lid. It's terrifying and feels like you're going to break it, but it's just a ton of suction in the middle. Once you have the lid open, you should be able to pull up normally on the large red lever at the top and properly close it (top first, then lid).

I have the same problem on the Dyson V10 Animal. I was afraid to apply too much pressure on the red tab, which needs to be pushed in the forward direction to open the canister. · I did not want to risk breaking the transparent clip at the bottom of the canister with a screwdriver as recommended above. · I found once I had opened it, I observed that the red clip locks onto an outpouched area on the main device (See picture with green arrow). · I found that the red clip will click forward if I apply pressure simultaneously on the grey column below the red clip (See picture with red arrow) · Hope this helps. · Update (08/19/2019)