Alex Minecraft King

So basically, every time I try to start up any version of Forge with the launcher, though I mainly use 1.10.2, the game will start to load up, and I get as far as the Mojang screen, before it crashes and the launcher comes back, with the 'It looks like you're using an unsupported modified version of the game' So, can anyone help with that? Or tell me how I can actually play my Forge versions Like I said it happens with all of them.