First off, I do not expect Avast to support software issues when running on Windows Insider Preview builds. I just figured someone might like to know since these builds eventually become release builds.
Initially was getting UNEXPECTED_KERNEL_MODE_TRAP while running Avast after update to Insider Preview build 17035. Could only boot in safe mode. Uninstalling Avast allowed system to boot. Updated to build 17040 and then tried to reinstall Avast. Halfway through install, even with all optional Avast components not selected, consistently got a green screen. Think it was bad pool header or bad IRQ request or something similar at this point. Prior to build 17035 install, had not been having any issues.
Have removed Avast for now and installed Bitdefender. Everything running fine now. Submitted feedback to Microsoft as well.
