virtualbox.org

I never gave my HOST antivirus a second thought. We use Symantec Endpoint Protection. When it flagged a file that I KNEW was OK from some other project I had to enter an exclusion for it to keep from being flagged again. it occurred to me that I never made exclusions for the VM's files or the VBox program folder. I told SEP to ignore everything in the VBox Program and the VMs home folders. The effect was immediate and pretty dramatic. Suddenly the VM ran a lot more smoothly and pages loaded faster in Firefox on the VM than they were before. SEP is a fairly intrusive AV application so if you use some other AV app it may not HAVE the same EFFECTS.

So it maybe worth your while to put in manual exclusion to your antivirus for both the program and the VM files.