Virus TI2 Desktop installation problem on OSX Yosemite 10.10.3

try booting the Virus into USB firmware mode before starting installer.
to do this:
- unplug virus power
- hold EXIT
- whilst holding exit, plug in power

then run the installer.

I always do this, when I upgrading, as I find it more reliable than the installer putting the Virus into firmware update mode.
though, I will admit, usually its not a matter of the installer finding it, it generally throws an error.

I assume its working generally, i.e. its not a USB setup, its just the installation...
(if you have not had it working at all, then usual things... try different USB ports, try using a USB hub, or direct etc)

if your updating an install, I tend to also uninstall previous version before I upgrade.

and of course, if in doubt email Access support... they will walk through problems with you.