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SOLVED: UltraVNC Can’t Send CONTROL ALT DEL on Windows 7 64bit or Server 2008 R2 and Screen Refresh Issues

UPDATE: Note that I have given up on UltraVNC and gone to RealVNC because it supports 4 monitors (and I find TightVNC just too slow when the screens are busy).  Pay the $30 for the Personal version and save the time.


Sooo, I needed a fast VNC that would support multiple monitors so I can run some digital signage and digital artwork remotely on Win 7 64 Bit.  Previously I had used the standard REALVNC but it has problems with running as a service in 64bit PC’s, which I had previously tollerated on my Windows Vista implementations.  It’s been a few years and so I took another crack at it and found that the current build of UltraVNC:

  • supports multiple monitors
  • supports Windows 7 and Server 2008 R2
  • supports 64 bit
  • supports Active Directory tie in


What it can’t seem to do is consistantly get past the Windows Login/Logon screen.  From several blogs, the cause is apparently that UAC has to be ENABLED, which in my case is not a problem, because I always leave UAC on under Windows 7.  CTRL ALT DEL usually has no apparent response from the host PC.  After playing with settings and reading blogs I found three suggested work arounds, two of which was a good one:

  1. Disable the CONTROL ALT DEL (C A D) requirement via the registry (this is a VERY bad idea in corporate environments that should get you fired).
  2. Click the blue wheel (Ease of Access) icon in the bottom left corner of the screen and select TYPE WITHOUT THE KEYBOARD – ON SCREEN KEYBOARD.  The problem with this option was that the screen would not refresh automatically… which is annoying.   See REFRESH SOLUTION below.
  3. I also found that putting the ultraVNC client into FULL SCREEN sometimes let me use the SEND CONTROL+ALT+DEL key


From I found the solution was to change the following settings in C:\PROGRAM FILES\ULTRAVNC\UltraVNC.INI


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  1. avatar

    Thanks for the tip. You’re a genius. Helped me out perfectly. Maximizing the screen allowed “send ctl alt del” to the windows 2008 server!

  2. avatar

    hmm, maximizing screen doesn’t work with my server 2008/sp2 connection, alas.

  3. avatar

    Good thinking, Ian.
    I couldn’t get onto a couple of win7 machines, but your idea of using the onscreen keyboard worked a treat. I just hold down ctrl + alt (on my keyboard) and clicked ‘del’ with the mouse.

    This should get my by until Uvnc devs work something out.

  4. avatar

    This helped me out also I used the full screen and the on screen keyboard + real keyboard combo and it got me passed the initial logon screen on windows 2008r2

    Thanks for this trick

  5. avatar
    Shaik Saheb03-15-12


    I am not sure what the problem is, but inspite of the above changes being made, I was not able to proceed. Any help on this will be greatly appreciated. Thanks

    • avatar
      Ian Matthews03-19-12

      Good Day. This did resolve my issue, but I will leave your post for others to comment on; perhaps others have alternate solutions.

      Thanks for visiting our site.

  6. avatar
    Daniel Beato04-06-12

    Or you can do CRTL+ALT+F4

    • avatar
      Nick Harvey05-02-12

      Not sure if this is related or not, but I was doing something that caused UltraVNC to prompt me “Make change to UAC registry to allow cad” (not sure what CAD is) and I clicked yes, now it works. ???

      • avatar
        Ian Matthews05-09-12

        Very nice… a little VNC voodoo

      • avatar
        Scott Goodhart08-29-12

        CAD= “C”trl+”A”lt+”D”el

  7. avatar
    Gary Schultz04-14-12

    I found that turning on Remote Desktop on Windows 7 systems and Windows 2008 servers allowed UltraVNC (tested with severial versions of it) corrected the Crtl+ALT+Del and other problems. Still researching why…

  8. avatar

    I have done all of this and it still isn’t working.

  9. avatar

    From spiceworks

    VNCScan works best for this but you can do it manually, also.

    1) “Start menu” -> “Execute” – > gpedit.msc
    2) Navigate to “Computer Configuration” -> “Administrative Templates” -> “Windows Components” -> “Windows Logon Options”
    3) Double-click on the “Disable or enable software Secure Attention Sequence” parameter.
    4) Check “Enable”, then select “Services” in the combobox.
    5) Apply the modification

    Worked great for me

    • avatar

      It works fine for me with W2008 R2
      Thanks a lot

    • avatar

      Thanks Sal,
      This is work very well with echovnc on windows7.
      Great tip!

  10. avatar

    Thank you sal, the solution worked for me.

  11. avatar
    Karl Bartz12-15-12

    Nick Harvey’s solution is easy to re-create:
    1. Logon to the Administrator account on the remote PC locally to get to the desktop.
    2. Send remote Crtl-Alt-Del command via UltraVNC from a client PC. [You will see a pop-up message that asks if you want to “Make change to UAC registry to allow CAD”.]
    3. Click “Yes” to allow changes to the registry to allow CAD.
    4. Click “Continue” when the next UAC pop-up appears.
    You’re done! You can now send the CAD remotely from the UltraVNC client to your Windows 7 Pro PC.

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