# Rubik's cube with one disoriented corner [duplicate]

I have been trying to solve Rubik's cube using beginner's method provided here: https://ruwix.com/the-rubiks-cube/how-to-solve-the-rubiks-cube-beginners-method/

I ended up with just one last corner which is not oriented properly as shown in the picture. I cannot seem to solve it using R’ D’ R D algorithm, it messes up the whole square when the corner piece gets oriented. Every time I try to solve the cube, it again has just one last corner disoriented. None of the algorithms mention one last corner case. they always talk about 2 or more corners disoriented. I don't understand. Can someone explain whats happening and how to solve it?

• According to @ChrisCudmore's comment to the answer below, it's likely that this is a Speed Cube that accidentally went through a "corner flip" (not a legal Rubik's Cube move), and became unsolvable in that manner. To fix it, flip that corner back: "Essentially, you rotate a layer 45 degrees, and then you can spin one of the corner pieces overhanging the edge in place." Commented Apr 8, 2019 at 14:57