3x3 cube, middle layer edges swapped - help!

[Tillie]

Hi,

I'm new to cubing but learned quickly how to solve both the 3x3 and 4x4 cubes however I have one issue (parity?) that appears sometimes when I'm doing the middle layer(s).

The technique I'm using is from this video:

https://www.youtube.com/watch?v=tYmtdFM1Zwk

At around 7:40 he's solving the middle layer and once there are no yelow edge pieces on the bottom side the whole middle layer should be solved. Sometimes when I do it two of the middle layers edges are swapped with each other and all the bottom edges are yellow which puts me in a dead end. As I cannot find anything about it on the internets I always have to mix the cube and start over hoping it wont happen again. But there must be some way to swap these middle layer edges with each other?? I get this with both the 3x3 and 4x4 cubes, they are both new and have not been disassembled at any point.

Video demonstration of my 4x4 cube with this issue:

 

[Randomno]

If you have middle layer edges in the incorrect place in the middle layer, use the alg to take them out.

 

[Cale S]

First you need to get one of the two edges into the top layer. You can do this by taking a random edge already in the top layer and inserting it into the middle layer edge you want to take out (using U R U' R' U' F' U F or U' L' U L U F U' F'). After you get it in the top layer, you can insert it into its correct position like you would normally.

 

[TDM]

Either do what Cale S said, or:
R2 U2 R2 F R2 F' U2 R' U R'
(this only works for this specific case though)

 

[Tillie]

Wow! Thanks for the fast answer and easy instructions, worked like a charm!