Since migrating to Windows 10, removing local administrator rights and increasing the UAC level for end users the following pop-up has been appearing to complain about definitions being out of date:
Do you want to run this app?
You should only run apps that come from publishers you trust.
Interestingly enough Symantec Corporation is detected as a publisher – so it is strange why it is popping up.
The Symantec Endpoint Protection Manager settings which are responsible for Windows notifications can be located under Clients (1) > My Company (2), Policies (3) and select Clients – Virus and Spyware [shared] (4):
Select Edit Shared: 
Now from the pop-up window select Miscellaneous (1) and finally select to either completely disable the Windows Security Center alerts or modify the warning threshold (2) under the Miscellaneous tab:
