Graphics Device Lost - Direct 3D

We’re seeing the following error when running our game on OSX machines running Windows 7 (BootCamp):

HandleD3DDeviceLost: still lost
Skipped rendering frame because GfxDevice is in invalid state (device lost)

Graphics info for the machines is:

Version: Direct3D 9.0c [nvd3dum.dll]
Renderer: NVIDIA GeForce 9400
Vendor: NVIDIA
VRAM: 241 MB (via DXGI)
Caps: Shader=30 DepthRT=1 NativeDepth=1 NativeShadow=1 DF16=0 DF24=0 INTZ=1 RAWZ=0 NULL=1 RESZ=0 SlowINTZ=0
desktop: 1920x1080 59Hz; virtual: 1920x1080 at 0,0

The game is apparently freezing after some amount of play time and then spamming the log file with these errors. This is from a standalone build created with 3.5.0f5. We’re thinking it’s a graphics driver issue right now, but haven’t been able to reproduce this due to a lack of similar machines to test on (this is from a client machine). Any ideas on a possible cause for the graphics device being lost?

This is a failure of the the multi-thread rendering introduced with Unity 3.5, I keep seeing it myself.

Someone here posted this toggle menu fix that allows you to turn multi-thread rendering off, you might see if this helps.

using UnityEditor;
class ExtraSettings
	[MenuItem("Extra Settings/Enable MT Rendering")]
	static void EnableMTRendering()
		UnityEditor.PlayerSettings.MTRendering = true;

	[MenuItem("Extra Settings/Disable MT Rendering")]
	static void DisableMTRendering()
		UnityEditor.PlayerSettings.MTRendering = false;

Thank you all for this I know it is a bit outdated but have the same issue. I copied the code put it in the folder got the option in the editor toolbar and clicked off MT. Rebuilt the standalone ran it on other pcs and still everyone has the same error. It runs fine sometimes for a long time other times it starts instantly. This is on a fresh install of Windows 7 with updated DirctX, Graphic Drivers, .Net, etc.

Am I missing something here?

Running GForce GFX 560.