I know that there was lots and lots of posts about the same problem for XPS 15 9550 not shutting down properly.
Unfortunately, I tried them all, and ended up in a sort of weird situation where I could not find a relevant post.
Today, out of sudden, my laptop started to reboot automatically few seconds after I shut down. As soon as I turned the computer off, the laptop would turn on again by itself.
To solve this problem, I tried various things on the internet, which did no help.
After some trial however, I managed to stop the laptop from starting automatically (I have no idea how).
But the problem is that, when I turn on the laptop and look at CPU uptime from the Task Manager, the numbers show that CPU did not just start from the time I turn on the laptop. Instead, it shows that CPU had been on for the whole time when I even turned the laptop off.
(For example, it showed that CPU was running for hours even though I just turned on the laptop.)
And only restarting the laptop or long-pressing power button will reset the CPU's uptime.
Hope to find a solution here. Thanks in advance!
When you do the normal Windows 10 shutdown, it does not totally shut the computer down. It can be running things while you think it is off. To stop this you can shut off Fast Startup. It will slow your boot up a little bit, but I feel it is safer. Here is a link that gives you instructions on how to do it.
I had the same problem, and tried the method suggested below. But, it did not work. I also tried changing a value for "PowerdownAfterShutdown" using Regedit, but it was not successful.
It has solved the issue by updating a new BIOS update, v1.2.14 A13 released on Sep 9, 2016. This is the second time that I experience the same issue. Interesting thing is that this happens over and over again after a bunch of new Windows 10 updates are updated. I guess this must be associated with something in the BIOS setting.
Even after two repairs sent out to Dell repair center, this issue does not go away. It does not happen all the time, but happens once in a while like once a month or so. Dell neither answers the root cause of the issue nor acknowledges that the system design is defective. No hope.
What worked consistently for me when in the 'won't power down-auto reboot' situation was to unplug the AC adaptor and only then power down.
No idea why. I'm awaiting a full replacement, this is but one of the issues I keep encountering.
Hello everyone, just to let you know that I encoutner the exact same issue.
When I try to power my XPS 9550 down or turn it in standby mode it turns ON automatically after 2 seconds. This can be very dangerous as the computer may burn if it is in a sleeve (it was very hot).
Please DELL, you don't have any solution 2 years after this issue was raised ?