Unable to switch to coherence mode.

Discussion in 'Parallels Desktop for Mac' started by joshkerr, Mar 5, 2007.

  1. joshkerr

    joshkerr Bit poster

    Messages:
    3
    I have two 30" cinema displays and am having an issue switching to coherence mode. I'm using the latest release of Parallels and get the following error message:

    Primary operating system does not support the screen resolution requested by the guest operating system. Select another guest resolution or review your video card settings.

    Any ideas?
     
  2. darkone

    darkone Forum Maven

    Messages:
    804
    coherence doesnt like dual monitors. try disconnecting one, switching to coherence and plugging it back in again.. cant promise, but worth a try.. try also a search of this forum as its been discussed many many times.
     
  3. joshkerr

    joshkerr Bit poster

    Messages:
    3
    I searched coherence and saw only one thread talking about multiple monitors and none had a solution.
     
  4. sjs

    sjs Junior Member

    Messages:
    16
    Yeah no solution yet... but you don't have to unplug the monitor. Just uncheck Use Multiple Displays from the dialog found via View > VM Configuration (or something like that).
     
  5. awk

    awk Bit poster

    Messages:
    3
    It seems to be related to using multiple monitors; as pointed out in another thread, Windoze has a limit of about 4096 pixels wide. If the total width of your extended desktop exceeds this limit, Coherence can't deal with it... I think. I would like verification of this, but this is what my experiments are telling me. I'm running a new Mac Pro 3-GHz dual quad core with three 20" monitors each with a resolution of 1680 x 1050... my extended desktop (with the 3 monitors side by side) is therefore 3*1680 = 5040 pixels wide. Doesn't work. When I reconfigure for either 2 monitors, or change the configuration in the Mac OS System Preference panels for two monitors above and 1 below, it works... sort of. Still have video buffer size issues. But it does start to work.

    Good luck. Would love to know more about this and hope the smart guys here at Parallel's central can figure out a work-around. They could at least document the problem better... Great program other that this issue... as an Engineer, having mutliple monitor support is a must have feature.
     
  6. drval

    drval Pro

    Messages:
    490
    I have no problem running two external monitors, except that, as has been reported, the smallest vertical dimension of the primary monitor sets the largest possible vertical dimension of the second monitor. In other words, the feature currently doesn't deal well with differently sized monitors. I have not yet tried three monitors and I do not know of anyone who has succeeded in running three monitors.
     

Share This Page