Mystery app preventing Windows 10 shutdown after update.

I have had exactly the same problem, along with at least the 66 other people who replied they do too. There is no App running in the Task Master. It is an App icon that does not show up when I look for it under my Apps, and only occurred after the update. Very annoying to have to click ignore every time.

It is not technically an app that is running (even though the message tells you that it's an app). I have discovered that it is actually a process that is running. I could never pinpoint the process, and, of course, there was no problem when I got a new computer.

However, the day I downloaded SMSListo, there was the message telling me an "app" was preventing shutdown. I looked, and there was an SMSListo process running. Uninstalling (but not reinstalling) SMSListo solved the problem.

Another poster here said he found that a process for his printer was running. A process, mind you, not an app.

To me it is obvious that one of Microsoft's infamous updates has permitted a lot of different processes to be interpreted as "apps" that are running.  Whether or not Microsoft will fix its update remains to be seen. I rather doubt that Microsoft will take the time to fix it.............

I recently received a new work computer and had the same issue. Eventually I found the app causing the issue, and you should be able to as well by doing this.

1. Initiate a shutdown
2. Cancel out of it when the screen telling you the app is preventing a shutdown shows
3. Open Event Viewer
4. Expend the Windows Logs section
5. Select the Application section
6. Look for an event that states "The following application attempted to veto the shutdown:" it should be one of the very first ones if you order by date/time descending. The name of the executable will be listed after the colon, if you don't recognize it, google it and you should find the program it's tied to pretty easily.

For me, it was BESClientUI.exe which is the executable for a system update tool my company uses that was running as a process. Closing that out before shutting down eliminates the issue but isn't ideal. Still trying to figure out how to prevent it happening without totally shutting down the check for running apps.

... and I thought, I got a Trojan/virus with the message unknown app blocking  shut down ...

VHV

I have finally managed to stop this annoying "app" preventing shutdown.  The thing is I cannot tell you exactly what I did to fix it.

I also had a problem the search feature in taskbar not working so was working on a work around for that, changing network settings to private

Refer to https://www.tenforums.com/tutorials/6815-set-network-location-private-public-windows-10-a.html

Testing a new user login and re-installing Cortana.  Somewhere along the mystery app error has disappeared.

Also I changed the login so that I do not have to input password every time I turn on the computer.

For the Cortana search issue I followed these instructions (Note: after doing this I could get the search feature to work until I shutdown and restart and then it reoccurs)  

**MOST FRUSTRATING since none of these issues were issues prior to windows updates grrr

WARNING: This solution may have yet unknown side effects, use at your own risk!

• "Win+X -> A" to open a cmd console with administrator rights.
• "net user /ADD Testadmin" to create the user Testadmin
• "net localgroup Administrators Testadmin /add" to add Testadmin to the Administrators. NOTE: The "Administrators" group name is subject to localization.
• Sign off your current Account and sign into Testadmin.
• Navigate to "C:\Users[ProblemUserName]\AppData\Local\Packages". You may have to take ownership of the Problem User's Userfolder.
• Rename the Cortana folder "Microsoft.Windows.Cortana...." and add the extension ".old"
• Sign off Testadmin and back into the problem account.
• "Win+X -> a" to open a cmd console with administrator rights.
• "start powershell" to open a new powershell with administrator rights.
• "Add-AppxPackage -DisableDevelopmentMode -Register "$(Get-AppxPackage -Name *Cortana* | Select -Expand InstallLocation)\AppxManifest.xml". This will redeploy the Cortana package.
• Reboot. Cortana and search should now be working.
• Optional: Remove Testadmin:
• "Win+X -> A" to open a cmd console with administrator rights.
• "net user /DELETE Testadmin"
• Delete "C:\Users\Testadmin"