Mystery app preventing Windows 10 shutdown after update.

As a retired federal tax software developer, my customers would not have accepted this kind of quality for so long.  

Step one - don't give me work-arounds - call it what it is A BUG!  Microsoft has more trouble saying "BUG" than "radical Islamic Terrorist"

Step two - Identify the program in question instead of a generic icon with no identity.

Step three - FIX IT!

Follow Up - Give us real problems instead of codes.  There are a lot of users that could fix their own issues if the Microsoft errors weren't so encrypted.  I have been around since before Windows 95.  I don't need (or want) a computer that tries to replicate a smart phone.

After much searching, and trying many, many suggestions, this is what eventually worked for me:-

Run Windows System File Checker

Your Windows PC comes with an in-built system file checker utility program. It can scan your system files and let you know if there is some corruption over there for which you get smashed with the error message “Task Host Window Preventing Shutdown”. You must follow these simple steps here to run the Windows System File Checker,

• Press the Windows Logo Key + X from your PC
• From the drop-down list select the Command Prompt(Admin)
• Click on Yes if prompted for permission. It will open the elevated command prompt on your system
• Now, type in the following command and press the enter button
• sfc /scannow
• Then, wait until the System File Checker continues the process of scanning. Press Y if the program asks for permission to apply the fixes for your missing system files
• Finally, Restart your PC once again and check if you can get over the problem there

I found the above on a list of several suggestions, which are on the following link, but the above was what removed the problem for me.

https://silicophilic.com/this-app-is-preventing-shutdown-in-windows-10/

We appreciate you getting back to us with the added information.

The app that prevents your device from shutting down is most likely part of the updated system or could also be part of the security certificates that was installed after you performed Windows Update. We can determine which specific app is that by ending the task of the same icon in the Task Manager. However, let's try to run the System File Checker tool first to fix and correct any improper settings in your computer system. Please note of the result.

We would like to ask for the screenshot of the shut down page where it says that there's an app which prevents you from shutting down, and also the screenshot of your Task Manager under the Process tab. This is for us to have a better picture of the issue and determine the appropriate advice.

Additionally, we also suggest that you run Power troubleshooter for possible help. To do that, simply type troubleshoot in the search field or Cortana, click on it in the search result, click on Power, then click on the Run the troubleshooter button.

Any update from you is highly appreciated.

Thank you, Lawrence Lib, for your reply.

I would first of all like to repeat (for the 3rd time) that the task manager does NOT reveal the name of this mysterious anonymous app. The only app listed as running is the Task Manager itself. Attaching screen shot of this.

Thanks also for your suggestion on using the System File Checker tool. Here is the result:

Microsoft Windows [Version 10.0.16299.248]

(c) 2017 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>DISM.exe /Online /Cleanup-image /Restorehealth

Deployment Image Servicing and Management tool

Version: 10.0.16299.15

Image Version: 10.0.16299.248

[==========================100.0%==========================] The restore operation completed successfully.

The operation completed successfully.

C:\WINDOWS\system32>

Thanks also for suggesting the Power Troubleshooter. The results are here:

As for a screenshot of the Shutdown screen, you may not be aware of this but the normal manner of obtaining a screenshot ("Printscreen") does not work on a Shutdown screen. If there is another method, please let me know. In the meantime, here is a transcription of that screen:

"Closing 1 app and shutting down.

To go back and save your work,click cancel and finish what you need to do.

This app* is preventing shutdown

Shutdown anyway (clickable rectangle) Cancel (clickable rectangle)"

Neither the System File Checker tool nor the Power troubleshooter had any effect. I still have the same annoying problem.

*(As I've mentioned mentioned before, no right or left clicking or hovering reveals the named of "this app").

Im amazed that over a year of this tomf*ckery and still no reply on this very specific issue. The usual MS tech checklist wont solve this issue, there is an app trying to close and there is no string value attached to its process name  (if there is its not showing it). I too have been having this issue and understand completely where you are coming from. You cant click on it, its a shutdown screen, you cant printscreen, its a damn shutdown screen. 

My only suggestion would be to somehow find a shutdown log of some kind, and see where it is hanging. I'm not sure how to do this myself yet, but thats what my troubleshooting mind is telling me

I was trying to help but you have, apparently, solved your problem. Good to know.

Thanks PJF, but you've misunderstood my post ---- I have NOT "solved" the problem; I have merely found an explanation.  The "solution" has to be found by Microsoft, whose "update" caused the system to misinterpret a background process as an application  Until that happens, other background processes (besides SMS Listo or Brother printers) will continue to be misinterpreted as applications.

you know what, on XP and 7, on occasion, I had that happen, it eventually stopped. I just spent that split 1/2 second to press the button force them/it closed and didn't give it another thought.

That analogy for the car to this, is a little off kilter. But I understand the point you are making.