I've got dual monitors on a Mac Mini. The primary monitor uses the HDMI port, and it works fine. The secondary monitor runs off Thunderbolt and a couple of week

I've got dual monitors on a Mac Mini. The primary monitor uses the HDMI port, and it works fine. The secondary monitor runs off Thunderbolt and a couple of weeks ago it started going black, randomly. This isn't a hardware issue, because I have used multiple cables and monitors, and I have used both Thunderbolt-to-HDMI and Thunderbolt-to-VGA adapters and I get the same issue. Oddly, the black screen still shows the mouse pointer, and if I take a screen shot it shows what the monitor should be displaying. The fact that it just started happening leads me to believe that it came with an operating system update, and it's probably a driver issue. Apple really needs to get its act together on USB.