When a solver app says your Rubik's Cube is unsolvable, it does not always mean the cube is broken. Most of the time, the entered colors do not match the real cube.
Still, impossible cube states do exist. A legal scramble can only reach certain arrangements. If a piece was twisted, flipped, swapped, or reassembled incorrectly, no sequence of normal turns can solve it.
Cause 1: One sticker was entered wrong
This is the most common issue. On a 3x3 cube, each color must appear nine times. On a 2x2 cube, each color must appear four times. If the counts are wrong, the input cannot represent a real cube.
Check similar colors carefully. Red and orange are easy to swap under warm light.
Cause 2: The cube orientation changed during input
If you rotate the whole cube while entering faces, stickers can land on the wrong face in the app. The color counts may still look correct, but the position data will be wrong.
Go slowly and keep the same front and top orientation.
Cause 3: A piece was twisted or flipped
On a 3x3 cube, a flipped edge or twisted corner cannot be fixed by legal moves. On a 2x2 cube, a twisted corner is a common impossible state.
If the cube was dropped, taken apart, or adjusted by hand, this becomes more likely.
Cause 4: The cube was reassembled incorrectly
Some cubes can be taken apart and put back together. If two pieces were swapped during reassembly, the cube may look normal but be mathematically impossible.
