If you're considering trying Win 10 build 14946, you might find this interesting. From Dona Sarkar of M/S.
Known issues for PC
If you have 3rd party antivirus products such as Bitdefender, Kaspersky Antivirus, F-Secure Antivirus and Malwarebytes installed on your PC – your PC might not be able to complete the update to this build and roll-back to the previous build.
No doubt it will work perfectly with Defender ! 
Hi all
Reinstall Norton Security on windows preview build 14946 no problems, seem to be stable updates ok will see with the next preview build if windows 10 updates.
regards
Ian
Hi all! I did try to install the previous Windows 10 Insider build 14942, and installation got stuck at 80%. I had to manually restart by using the power button, and thank God my laptop went back to build 14936. When Microsoft does all the installation preparations, shouldn't they look on what I have installed and *know* that it will cause a problem, and warn me somehow?? I did remove Norton Security with the removal tool, and installed 14942. Things seem to work ok until I reinstalled Norton Security, and then nothing worked anymore! My laptop was getting stuck on the "welcome" screen right after I entered my password!!! This was not a little problem, it was a major one!!! I mean there used to be problems with other preview builds like 14328 and 14332, but all you had to do back then was to put the AV in "silent mode" for a few days until the problem as fixed and Norton did fix it! Anyway, I managed to go back to 14936 again, but now 14946 is ready to be installed, and the problem is not solved yet! I keep postponing the installation hoping that someone will come up with a solution! From what I hear, 14946 is a Redstone 2 preview, so Norton will have to deal with this sooner or later, so why wait until the spring when Redstone 2 public Windows 10 release is supposed to be available?
Kind regards,
Serafim