Kaseya Community

Black screen with VNC connection

  • You successfully establish a VNC session, but only get a black screen.

    There are 2 reasons that this can occur,

    1. XP supports multiple local log-ons to the same machine. The first user the logs on is given screen 0, if a 'switch user' happens, screen 0 is blanked, and the new user gets screen 1, and so on. VNC is only able to'see' screen 0.

    2. The screen is very active. If a user has a high movement screen saver such as a picture slideshow running, VNC is never able to capture the image before it changes. This can usually be overcome by right clicking on the title bar and sending a ctrl-alt-del. This can often stop the screen saver, and allow VNC to catch up.

    3. Change the router setting to use an MTU size of exactly 1500. VNC can have issues if the MTU is lower than this size as the screen data packets become truncated and this causes loss of screen data.

    4. From an RDP connection or from the console type the following command

    TSCON 0 /DEST:console

    If RDP has been used to connect to the remote machine at any point after power up and before the VNC session was established, RDP will have altered the screen number, and VNC will not be able to connect again until a reboot takes place. This command will reset the screen number and allow a connection. This is going to be corrected in VNC version 4.1.


    Legacy Forum Name: Black screen with VNC connection,
    Legacy Posted By Username: jnuttall
  • Are you sure the VNC black screen issue has been resolved? I frequently get this on Windows Server 2003 machines, including servers where I am absolutely sure that no one else is logged in.

    I just tried connecting to a 2K3 server and got the black screen. With VNC still running, I did an RDP session to the server console, and I saw this error message: WARNING: The ServiceHelper hook entry could not be removed from the registry. When I clicked OK it said that VNC had been unregistered. I then issued the "TSCON 0 /DEST:console" command and it terminated my RDP session. I then reconnected via VNC and it worked normally.

    A workaround is to connect to these W2K3 servers via TS, but sometimes you want to see exactly what they are seeing at the other end.


    Legacy Forum Name: Agents,
    Legacy Posted By Username: David_Schrag
  • I as well as my other techs get this every now and then . It just seems to happen and then go away. Weird

    Legacy Forum Name: Agents,
    Legacy Posted By Username: seangoss
  • This is still a problem. As far as I can tell, once you've connected to a W2K3 server via TS (whether or not through Kaseya), you can't then connect to it via VNC until you've rebooted it.

    This is a big problem if you are trying to work in partnership from your office with a tech who is on site.


    Legacy Forum Name: Agents,
    Legacy Posted By Username: David_Schrag
  • Any thoughts / progress on this? It's still a big problem for me.

    Legacy Forum Name: Agents,
    Legacy Posted By Username: David_Schrag
  • Hi

    I have just encountered this "Black Screen" upon connection with VNC. To clarify, once a remote connection is established, nothing but a black screen appears on the console machine.

    After checking, it appears to be a problem on the PC used on the VSA console side.

    All I get is a black screen when I use a XPP (DELL)machine, which had been working until some video issues on the machine came up recently in regards to the driver being used (Nvidia vs Microsoft driver). Attempting the same connection on another machine (clone), the connection was fine, which, indicates that there is a driver issue on the console machine (Dell).

    There are basically2 things that have been changed on the Dell, which is the problem now. DirectX9 installed, and the NVidia driver was installed.

    No solution as of this writing.

    Perhaps that is the cause of your Black Screen problem as well.




    Legacy Forum Name: Agents,
    Legacy Posted By Username: shickey
  • It's the NVidia driver. You will have to change the driver to successfully use VNC.


    Legacy Forum Name: Agents,
    Legacy Posted By Username: Alan M
  • I'm experiencing this problem with Windows 2003 servers that are not using NVIDIA drivers. For example, one of my own servers is a Dell server with an XGI video driver.

    Legacy Forum Name: Agents,
    Legacy Posted By Username: David_Schrag
  • Sorry, I have only seen this problem with NVidia drivers and was easily solved by reverting to a previous version. Maybe you should try different drivers for the video card you have.Send

    Legacy Forum Name: Agents,
    Legacy Posted By Username: Alan M
  • Imported Empty Post

    Legacy Forum Name: Agents,
    Legacy Posted By Username: mnikravesh
  • Imported Empty Post

    Legacy Forum Name: Agents,
    Legacy Posted By Username: mnikravesh
  • This happens to us frequently after somone has RDP to a computer/server. We found a work around but it only works 1/2 the time. Just run the lock workstation script and try again.

    Matthew


    Legacy Forum Name: Agents,
    Legacy Posted By Username: mnikravesh
  • Dear Kaseya employees:

    This is still a problem and we haven't gotten a response from you in this thread. Is this something you at least acknowledge and are working on, or do you think those of us who have experienced the problem are just suffering from a peculiar set of circumstances?

    David


    Legacy Forum Name: Agents,
    Legacy Posted By Username: David_Schrag
  • The solition was posted in the first message on the thread:

    You need to run this command on the computer that's affected:

    TSCON 0 /DEST:console

    I've found that it runs fine via a script and VNC works after that.

    Script Name: Fix VNC Black Screen
    Script Description:

    IF True
    THEN
    Execute Shell Command
    Parameter 1 : TSCON 0 /DEST:console
    Parameter 2 : 0
    OS Type : 0
    ELSE


    Legacy Forum Name: Agents,
    Legacy Posted By Username: qrysdonnell
  • I believe this is an issue with fast user switching and logging off. If you have fast user switching enabled in xp and you try and vnc into that pc while someone is logged on....you'll connect, but you'll get a black screen. A sure fix for this is to disable fast user switching. I haven't createda script or anything yet, but I'm sure all you'd just have to do is togglea registry setting.

    Steven


    Legacy Forum Name: Agents,
    Legacy Posted By Username: Steven808