2 Replies Latest reply: Nov 25, 2012 1:44 PM by den.thed
ac1981 Level 1 (0 points)

Hi there,


I have a Philips monitor as a second display for my iMac. Whenever I plug in my printer to one of the iMac's USB ports (haven't sorted out a wireless connection yet), the second display automatically dismounts. To get it back I have to unplug the printer, then disconnect and reconnect the mini-display port connector for the second monitor.


Any ideas why this would happen? Can't think it's a power issue as both the printer and the monitor have their own power, and this doesn't happen when I plug in flash drives and other devices using the USB ports.


Any help with this annoying problem would be much appreciated!


iMac (21.5-inch Late 2009), OS X Mountain Lion (10.8.2)
  • BDAqua Level 10 (122,276 points)

    Sounds a bit like it might be a Ground loop on the Printer.


    Open Console in Utilities & see if there are any clues or repeating messages when this happens.

  • den.thed Level 7 (25,992 points)

    Sounds to me like you are either disturbing the power to the Mini DisplayPort or actually moving the Mini DisplayPort plug causing it to lose connection


    I suggest getting a Mac compatible 4 or 7 Port Hub to hot plug your printer and other USB devices into. That way you will not have to reach around to plug in USB devices and/or disturb other connections.