The first thing you have to do is run a command to see which device is preventing your system from going to sleep mode. To check this, open CMD with Administrative privileges. And type the following command.
It will show you the device name under “System". Now next you have to tell to Power Management System to ignore that particular device and let your system to sleep mode when requested. Following command has to be executed with exact device name you get in the result of above command.
For example suppose you get “High Definition Audio Device", then the command will be like this.
powercfg –REQUESTSOVERRIDE DRIVER “High Definition Audio Device" SYSTEM.
Now Power Management System will ignore this device and doesn’t create any issue to put your system into sleep mode.
Windows 10 have Cortana option that allows you to speak and Cortana will open it for you by listening what you speak. If the issue occurs after updating your Operating System to Windows 10, then it might be Cortana that is creating trouble and won’t let your system sleep.
So to disable Cortana, type Cortana in Start menu and open “Cortana and Search Settings".
Disable the option of “Hey Cortana" by swapping the slider.
This will solve the issue for users who have upgraded their Windows to Windows 10, and cannot put the system into sleep mode.
Check Power Options for sleep option adjustment
Go to Control Panel –> Hardware & Sound –> Power Options –> Edit Plan Settings.
Here you will see options that when you want to put the system to go to Sleep mode. Check the settings if it is not set to “never" option. If it is, then set settings according to your requirement.
The solutions are tested and verified. Hopefully, you will be able to disable audio stream which is creating an issue for a system while going to sleep mode. Thank you.