Glad I found this post as I have had similar issues ever since purchasing my TI2 Polar 3 months ago.
I have always wanted a decent Synth, and when I found out about the Virus TI, I just had to get one, as it would integrate fully with software. But the problems I am having are really hampering my productivity, as I when I have to keep on closing my DAW (cubase 5)to restart my Virus you lose the flow 
I get Various issues with my TI, but the most common issue is random sound crashes(sounds like a high pitched saw tooth wave most of the time) on the Virus channels. If I restart my DAW and the Virus it usually works fine again for a while, and sometimes I can work for an hour or so without an issue, but other times it can happens every few minutes. This happens with only 1 sound open, but appears to happen more frequently when I have more than 1 virus midi channel in use. (panic doesn't stop the sound) So I am also concerned about this damaging my speakers, as the sound gets quite loud. Had headphones on the other day, and it wasn't pleasant.
Also, when I have a cubase project open that is using the Virus, when I close this project and open another which is using the virus, the Virus nearly 100% of the time stops working. So if I change projects, I have to close Cubase totally, and reset the Virus.
I have found recently, that say for example I have an instrument on VIrus Midi 2, and the instrument gets the high pitch noise, usually the other midi channels are ok, so if I drag my instrument within VC to Midi 3, and then configure the channel on my daw from 2 to 3, it works again. But channel 2 remains messed up until both my daw and the Virus are restarted.
Sometimes when this happens, it causes the other channels to act very strangely, and the lights on the LFO section on the Virus flash really fast and not in temp. And other times, I get no sound at all from the virus until I restart.
It also just locks up sometimes, with the virus TI display frozen, only way to get around this is to remove the power from the Virus. Sometimes on a fresh reboot of my pc and Virus, it doesn't work at all, and i have to restart the virus again to get any sound.
I also get issues with the Atomizer, it works for a few mins, then stops. Both in single mode and via USB. Keys stop changing the effects randomly.
I thought this was most likely a USB issue, or an issue with my old DAW Cubase SX 3. But I have tried setting up the virus on all USB ports, and with only my Mouse/Keyboard and Cubase Dongle plugged into USB, but the issue still occurs.
I thought it was down to my PC/daw, so upgraded at Christmas, and updated to Cubase 5, but the issue hasn't gone away:(
Does this sound like a hardware issue? I am almost regretting spending so much money on my TI, as although I love it when it works, the issues I have are killing my productivity.
I have 2 PC's in the house, a dual core with XP 32bit, and a quad core with Windows 7 64. I get the same issue with both PC's. All drivers up to date etc.
I have tried all OS available on the site, including the latest, but the problem just won't go away, any help would be greatly appreciated.
Many thanks
