Laplink Remote Control Session Results in a Black Screen

Author Scott M on January 30, 2012 | Print | Bookmark
Last updated on April 6, 2012

Document relates to: Laplink Gold (all versions), Laplink Everywhere


SUMMARY

When I open a remote control session, the connection is completed; however, I get a black screen or the host computer freezes. What is wrong?


CAUSE

Black screens occur when Laplink is unable to correctly send video information across the connection. There can be several reasons for this, but the primary reason is that the HOST computer’s video driver is not Windows Hardware Quality Labs (WHQL)-certified.

Many manufacturers of high-end video cards use accelerated display adapters that send all, or most, of the video changes, or calls, directly to the video card. The approved method of sending those changes is through the Windows Graphic Display Interface (GDI). The GDI manages what you see on the screen and controls all video processes. Laplink, like all remote control and video conferencing applications, inserts a dynamic link library (DLL) into the GDI in order to monitor video call processes. As calls occur, Laplink filters the call, copies it, and sends it across the communications link to the Guest’s display adapter. If the call goes directly to the video card, bypassing the GDI, Laplink cannot send changes from the Host computer to the guest computer. Since no graphical information moves across the communications link, a black screen results or the screen freezes.


SOLUTION

Several changes can act as solutions or workarounds to this problem.

  1. Confirm that you have latest version of Laplink. Keeping Laplink compatible with today's accelerated video drivers frequently requires changes to our application.


  2. Reduce the number of displayed colors. A color setting greater than 16-bit (High-color) causes video calls to be processed directly by the video card, automatically bypassing the GDI. See Technical Document 245: Changing Windows Video Settings for more information.


  3. Check with the video adapter manufacturer to ensure you have the latest WHQL-certified driver. See Technical Document 114: How Do I Discover What Type of Video Display Adapter I Have and Update the Drivers? for more information.


  4. Depending on the video card you have, you may have additional options. Look in the Display Properties on the Host computer for any type of setting that allows you to disable Bitmap/font caching, Direct Draw, GDI-patching, or other acceleration features. Some video cards allow you to change some or all of these features. Experiment with disabling different groups of acceleration features until you find those that you can leave enabled.


  5. If none of the previously discussed solutions work, you can replace the video driver with the Windows Standard VGA driver. This option is not available for computers running Windows NT or Windows 2000. See Technical Document 119:How to Configure a Video Card to use a Standard VGA Driver for more information.
    •  
      1. From the Windows Start menu, point to Settings and click Control Panel.

      2. Double-click System.

      3. Click the Hardware Profiles tab.

      4. Copy the original configuration and name it Laplink.

      5. Reboot, selecting the Laplink profile.

      6. Once you've reached the desktop, follow the above steps to install the display adapter for Standard VGA.

      7. Reboot Windows.

      8. When you need to remote control this computer, boot into the profile listed as Laplink. Otherwise, you can boot into the Original Configuration Profile for your regular tasks. 
    • Note: In nearly every case, setting the Host’s video driver to a Standard VGA driver will allow the Guest computer to correctly view the Host. However, most users will find this solution primitive for their general day-to-day work. If a Standard VGA driver appears to be the only solution, configuring a Hardware Profile that uses the VGA driver can minimize the impact of changing the configuration. Here are the steps:


This Article can be found by searching for:

Keywords: Remote Control: Video errors, Remote Control: Freeze, Video Errors: Black screen, Video Errors: Blank screen

Platforms: Win95, Win98/SE, WinNT, WinME, Win2K, WinXP

Article#: 128

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Category: Laplink Gold, Laplink Everywhere

Last updated on April 6, 2012 with 4182 views


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