Quote Originally Posted by niall2 View Post
Windows Defender will not work with Spybot, or any other antivirus program I have tested so far, on Windows 10.
Windows Defender and Spybot v2.4 were working together for me on Windows 10 build 10162 (and earlier builds) up until about the time that the installer for Spybot v2.5 was placed on the desktop.

I've just successfully installed Malwarebytes Free (so very similar to Spybot Free) on Windows 10 and Windows Defender is still working.

Spybot Free is not an anti-virus. It should work with Windows Defender/MSE, just like it has on previous versions of Windows.