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DO NOT use “Displays” in “System Preferences” via the Ion Desktop Client to change the display resolution on the remote machine (running Ignision SE).  This may make it impossible for you to interact with the remote machine via the Ion Desktop Client because the display may become distorted.

Follow these steps when you need to change display resolution on the machine running Ignision SE:

  1. Logout from your session on the remote machine by selecting “Log Out” from the Apple menu.
  2. Close the connection’s tab (the tab will not close on its own).  Note that the Ion Desktop Client is not currently notified when the user logs out of the remote session.  This gives the impression that the remote system has hung or crashed or become unresponsive when in reality the remote machine has simply disconnected.  Nothing is hung or crashed.  All you have to do is close the tab.
  3. Wait long enough to allow the Mac to complete logging you out (usually 5 or 10 seconds).
  4. Change the display resolution setting in the Ion Desktop Client connection properties.  Note that display resolutions in the Ion Desktop Client are specified as WIDTHxHEIGHT, e.g. 1920x1080 or 1280x800.
  5. Reconnect to the machine running Ignision SE.


Ignision SE currently supports the following display resolutions (provided that OS X has then configured): 800x500, 800x600, 1024x600, 1024x640, 1024x768, 1152x720, 1152x864, 1280x600, 1280x800, 1280x960, 1280x720, 1280x1024, 1360x768, 1366x768, 1400x875, 1400x1050, 1440x900, 1440x960, 1600x1200, 1600x900, 1680x1050, 1792x1344, 1856x1392, 1920x1080, 1920x1200, 1920x1440, 2560x1440, 2560x1600, 3840x2160, 5120x2880.

If your display becomes distorted because you accidentally do something other than the steps listed above then switch to the user’s session on the physical Mac machine console (i.e. display, mouse, and keyboard connected to the Mac) and log out the user via the Apple menu. Then you will be able to successfully reconnect using the Ion Desktop Client.

*** ATTENTION ***

OS X only provides display resolutions that are compatible with the monitor/display that is physically attached to the Mac.  Since most modern systems have an LED [flat panel] display attached and those displays only support one native resolution, e.g. 1920x1080 or 2880x1800 or 3840x2160, you will usually only see one resolution available in the “Displays” panel of System Preferences – even when you hold down alt/option and click the “Scaled” radio button.

This poses a problem for Ignision SE because it can only provide the resolutions known by and available to OS X.  Therefore it is necessary to add the resolutions required by the Ion Desktop Client and/or an RDP client to OS X in order for remote connections to use the resolutions they desire.  For example, if the connection in the Ion Desktop Client is configured for 1920x1080 resolution and the machine running Ignision SE only supports 1440x900 then 1440x900 will be used on the Ignision SE machine and the display data sent to the Ion Desktop Client will be scaled up (inflated) to make it as big as the 1920x1080 window size of the Ion Desktop Client.  Likewise, if the display resolution on the Ignision SE machine is larger than the window size of the Ion Desktop Client then it will be scaled down (shrunk) to fit.  Scaling often results in some visible distortion.  When you need pixel perfect accuracy (no distortion), disable scaling in the Ion Desktop Client.  This will provide scroll bars when the remote display is larger than the Ion Desktop Client window size and will center the remote display in the Ion Desktop Client window when the remote display is smaller.

One of the upcoming features of Ignision SE is the ability to add custom desktop resolutions, however this feature is currently incomplete due to recent changes in the way OS X manages display/screen resolutions.  For now, we recommend using SwitchResX (http://www.madrau.com/) to manually add the custom resolutions needed by all users connecting with the Ion Desktop client and/or RDP client.