Ubuntu shuts down instead of suspending

Solution 1:

I have the same issue with an XPS 13 9350 and Ubuntu 16.04. The issue was resolved for a little while when I followed this solution: Sony Vaio FW350 reboots instead of waking up after sleep/suspend

Now it's randomly back to shutting down instead of suspend.

You can click the suspend button in the top right menu (under the gear icon) while waiting for a solution, although even this works inconsistently on my XPS 13.

Solution 2:

I have Ubuntu 17.10 & Win10 dual boot and I recently had the same issue.

What worked for me is forcing Win10 to a full shut down, then the Ubuntu suspend process was back to normal.