Please provide more information:
- Is there any change before the problem happened? Such as hardware replacement, and software installation?
- Is there any 3rd party protection/anti-virus tool?
- Please check the System event in Event Viewer to confirm if there is any related event has been logged.
Go to task scheduler and look for: \Microsoft\Windows\PI and you will notice "SecureBootEncodeUEFI" task.
Disable it, or create a new one here with identical settings, except selecting "run whether user is logged on or not" this time. Both ways should get rid of the annoying pop up.
Hope this resolves your Query !!
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