[remote "mainstream"]
        fetch = +refs/heads/*:refs/remotes/origin/*
        url = git@github.com:FreeRDP/FreeRDP.git
[remote "origin"]
        fetch = +refs/heads/*:refs/remotes/origin/*
        url = git@github.com:pjd/FreeRDP.git
[branch "master"]
        remote = origin
        merge = refs/heads/master


> git checkout -b mcs_fixes mainstream/master
fatal: git checkout: updating paths is incompatible with switching branches.
Did you intend to checkout 'mainstream/master' which can not be resolved as commit?

> git fetch mainstream
From github.com:FreeRDP/FreeRDP
 * [new branch]      maintenance -> origin/maintenance
 + 1ba29ad...41558e4 master     -> origin/master  (forced update)

> git checkout -b mcs_fixes mainstream/master
fatal: git checkout: updating paths is incompatible with switching branches.
Did you intend to checkout 'mainstream/master' which can not be resolved as commit?