Conflicting Module Manager versions found.

DialogBox

So, by a reason or another, you ended up with TWO different forks of Module Manager in your rig.

Well, you need to choose one (obviously), and once you make your mind The Module Manager Watch Dog will not ask you again, but will automatically fix the installment using your choice.

If you ever decide to change your mind, delete the file <KSP-Root>/PluginData/ModuleManagerWatchDog.cfg and install the desired fork. You may want to remove the undesired one to save a reboot - see the How-To for how to install manually MM/L (or MM (Forum)).

Option I : Keep MM/L

This is my personal fork of Module Manager, aiming to fix some non functional bugs while keeping compatibility with the original Module Manager.

Option II : Keep MM (Forum)

Obviously, you can use the Official Module Manager from Forum.