I wonder if it's possible to start the MATE Desktop when needed and don't set graphical.target as standard.
installing MATE Desktop is no problem with dnf group. But startx always says X Server is offline etc...
What am I doing wrong?! Sometimes I just don't want to do stuff with nano/vim etc...
Edit: Using Fedora 23 Server in Virtual Box (testing)
This should cover most bases:
yum -y update kernel
and reboot
yum -y install dkms kernel-devel kernel-headers
yum -y install epel-release
yum -y groups install "MATE Desktop"
reboot
It's important to install the VirtualBox Guest Additions after installing MATE so that they find the X Server installation. That way they arrange the necessary graphical drivers. Finally, to avoid having to setup a graphical default target;
echo "exec /usr/bin/mate-session" >> ~/.xinitrc
startx
If you still get that "X Server is offline" issue then try yum -y groupinstall "X Window System"
and reinstall the VirtualBox Guest Additions.
As was commented above, this would have been better asked on Unix & Linux. Comprehensive instructions for installing various desktop environments can be found there.