I downloaded an old version of Forge then put a mod on it, it wasn't compatible so I deleted Forge from 'versions' and downloaded a new one.
When I opened the Minecraft launcher again, it only showed the old deleted Forge, and when I try to open it, it says
The version you are trying to play inherits properties of an unknown version
How do I completely remove this old version of Forge so that Minecraft will recognise the new one?
Best Answer
I suggest using MultiMC.
It allows you to create multiple instances of Minecraft, with or without forge. And it keeps them seperated, so that nothing can interfere with an instance.
It is free and fairly low weight.