While you are Shutting Down your computer a message should be displayed 'It is now safe to switch off you computer' then it is a mark of your computer shutting down safely. But when a message 'Windows Shutting Down' then it is not safe to turn off, when any program is running on the computer.
It is necessary to close all the programs before your shut down your PC and if it is not done, the computer waits for the program to close. Whenever a new software is installed this problem may occur and then you may need to also check USB devices, task scheduler, virus scanners, etc. and reinstall them if necessary.
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