升级Ubuntu 16.04之后报错解：

A start job is running for Hold until boot process finishes up (Xmin Xs/no limit)

解决方法：

Go in your safe mode by hitting SHIFT key or ESC. select networking , then drop to root prompt. Then run following commands.

sudo apt-get remove plymouthsudo apt-get remove xserver-xorg-video-intel

Now, reboot,

When you reboot, still you may get black or purple screen,

Press Ctrl+Alt+F1 and login with your username and password.

Then run following commands.

GDM ie Gnome display manager was also causing problems for me, so following step was essential for me

I switched to lightdm from gdm3 as display manager.

sudo apt-get install lightdmsudo dpkg-reconfigure lightdm

When you are prompted, select default display manager as lightdm

Now I was back with desktop , without dash or unity but only icons and wallpaper. now run this.

sudo apt-get install ubuntu-desktop

Now, reboot after this.

The desktop is back!

now, you can install intel graphic drivers again,

sudo apt-get install xserver-xorg-video-intel