OEM Win11 Pro Workstation will not power down, immediately restarts normally

[808Beachbum]

Attempting shut down by Start menu power option; lock screen power option; terminal window shutdown command; physical power button short OR long press; all result in same: Powers down seemingly normally, but within three seconds of physical button power light going out, it restarts. Operates normally otherwise, apps all function, updates are current, etc., and it has normally shut down completely as of a few days ago. Numerous app installs and new machine set up tweaks later over a week or so, unable to shut down today. Dell 3450, Win 11 21H2, build 22000.613
I have changed the power button, sleep, and fast start options in light of similar reported issue, to no effect.

 

[808Beachbum]

Update...

By tapping F12 during restart, I was able to run ePSA diagnostics, both quick and full, with no issues found. BIOS version is 1.5.1, ED.2.4.8

The initial issue persists...

 

[808Beachbum]

Update...

Opened service ticket with Dell 4/17/22. Over the course of a slow email conversation (One to two days between responses), and so far no phone call after two requests, I have run an ePSA diagnostic and made other adjustments and tried other processes at their direction. They now want to send out a tech to replace the motherboard and hard drive. I requested to have their tech add some memory, which I was willing to pay for, since their tech would have the guts out of this anyway, but they are unable/unwilling to do so. I guess the hours I spent setting up the system, installing mainstream apps, and mildly personalizing the system was wasted...and I will have to do it all over again once they change the MB. Their idea of "customer service" is quite different than mine, given this new, $2,000 machine is not a month old yet.

 

[808Beachbum]

Update...

Dell was out today and changed the motherboard after the tech made a few checks to verify status. This solved the original issue of being unable to shut down. Unfortunately, the replacement SSD they sent had no OS installed, so my original one had to be re-installed. Everything seems to be working fine now.

 

[DaiB]

I have a similar problem on my new Dell Inspiron 3910. Sometimes moving to Sleep or Shutdown within Win 11 the PC comes back to the login screen and I have to do a hard shutdown i.e. holding power button down. I suspect one of the bits of software I have installed but this problem still happens even when I have used Task Manager to close all Apps prior to shutdown. I will be updating the BIOS but sadly Dell doesn't list the fixes in the later BIOS.