Storage is a big problem early on in TCG Card Shop Simulator, with players dropping their boxes behind the counter or wherever they have space. It isn’t great, and a storage room and door taunt you throughout your first few hours of gameplay that seemingly can’t be unlocked.
No matter how much money you get early on and how many store upgrades you buy, the door never unlocks, leading many players to believe it’s not possible to get the storage room yet. There is, however, a way to open it—so long as you progress far enough into the game.