AntiVirus for Mac running parallels I'm using OS X 10.10.1 on my Mac. I use Parallels Desktop 10 and VMware Fusion 7.1. I do use windows a lot on Parallels and Fusion (Several Virtual machines). Windows 8.1,7 and XP. I've installed Avast free AV on OS X. Do i need to install separate Anti viruses on VMs ?? or do OS X Avast antivirus detect Windows viruses and malware ? Please explain. Thanks :)
Any virtual machine installed will require its own, self-contained antivirus program. For example, I run Parallels Desktop 9 with XP, Windows 7 and Linux CentOS 6 VMs. On XP and Windows 7, I use Microsoft Security Essentials and ClamAV on the Linux VM. On OS X, I am running Kaspersky Internet Security.

The reason that each OS requires its own A/V software is that each VM is a self-contained environment that is essentially sandboxed. Although there is some sharing mechanisms in place, essential services, e.g., antivirus, cannot cross OS boundaries. To allow so would be a serious security vulnerability.