I have the forge 1.6.4 and 1.8 client on my minecraft but don't use the 1.8 one. When I try to use the 1.6.4 one it crashes minecraft on startup.
I drag and drop my 1.6.4 mods into my mods folder in .minecraft and open the game, I then select Forge profile then change it to 1.6.4 forge instead of 1.8 and save, when I hit play the minecraft game doesn't open and nothing happens.
Why is this? Has it got something to do with the 1.8 bit?