Windows Technical Preview Build is a preview release, so not everything goes as planned .
Here are some reports regarding 3rd party antivirus tools which have been tried on Windows Technical Preview builds. The following AV software seem to work fine and compatible:
AVG 2015 internet security
Bitdefender antivirus free edition.
McAfee VirusScan Enterprise 8.8 Patch 4
Sophos Endpoint Security and Control, version 10.3
ESET Endpoint Security
Vipre Business Edition v7.0.5711
360 Total Security
Windows 10 TP comes with Microsoft’s anti-malware package i.e. Windows Defender. You have to wait till the final build is released to see 3rd party antivirus software to be 100% compatible.