Windows 10 was released by Microsoft on July 29th of 2015. Even though several months has already passed, millions of users using it, it's not entirely prime time ready. One of the features that is pretty annoying is Windows Defender which seems to be incompatible with some applications (namely VPN) and causes CPU spikes up to 100% constantly. Fortunately there is a way to disable it.
Solution
Disabling Windows Defender in Windows 10 can be done from GUI, but the problem is it can be quickly restarted by some apps again. To permanently disable it's functionality one can add those simple registry entries.
To disable built-in antivirus simply save this code into file and run it, or go into Registry Editor and modify it manually.
Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender] "DisableAntiSpyware"=dword:00000001 [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender\Real-Time Protection] "DisableBehaviorMonitoring"=dword:00000001 "DisableOnAccessProtection"=dword:00000001 "DisableScanOnRealtimeEnable"=dword:00000001
[wpdm_package id='5141′]
If you would like to revert those settings, simply delete those entries or save below entries into .REG file and run it again. It should cleanup the settings for you.
Windows Registry Editor Version 5.00 [-HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender]
[wpdm_package id='5143′]
Notes
Please note that Windows Defender is security software. Before disabling it be sure what you are doing.