I have an HP Color Laserjet CP1215 printer attached to both my old XP machine and a newer Vista machine through a USB switch. The XP machine will print, but the Vista machine shows that the printer is not connected, and won't print. I had an "Unknown Device" show up in Device mangager, uninstalled it, rebooted. On reboot it shows the device as being installed correctly, then shortly reverts back to "unknown device", and get a red "X" in printer icon at the bottom right hand side of the screen (quicklaunch toolbar). The printer works OK if I hook it direct to the computer with the USB cable. What might be the problem? Is it the switch or something in Vista that needs to be fiddled with? The switch is a 4 Port KVM model SWIT-USB 421 (StarTech).

How did you install the printer...did you install connected directly to the Vista machine? Or did you just connect and start using it?

I originally installed the printer connect directly to the Vista machine. Also installed directly to the XP machine. Then I put in the switchbox, and connected the printer and each machine to it.