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How to fix Cisco VPN Client error 442 on Windows Vista

Everyone has dealed with Cisco VPN Client on Vista probably knows the notorious Error 442 - Failed to enable virtual adapter. AFAIK this is a bug from Cisco that stays unfixed for at least 5 months (from the version 5.0.00.0340 released on May 2007 uptill now). Whether it is Cisco or Microsoft to point the finger at, i really don’t know.

So … if you come to this post through google, you probably already tried this Cisco advised work-around:

Run cmd as Administrator and execute the following command:
reg add HKLM\System\CurrentControlSet\Services\Tcpip\Parameters /v ArpRetryCount /t REG_DWORD /d 0 /f

It just doesn’t work ( at least everytimes i work with Error 442 ). What you should do is:

  • Deinstall the client
  • Activate the real Administrator account ( for detailed howto see this post )
  • Restart, then log into the administator account
  • Install the file as normal ( right-click on it, choose “Run as Administrator”)
  • After the installation finishs, restart again.

The client should work now. If not try to remove the Deterministic Network Enhancer protocol first, then reinstall VPN

Some people say the removal of Microsoft SQL do the trick (strange, erh ?), or simply turn on Media Sharing in the Network and Sharing Center. I haven’t tried this, so if it fixes your problem, then good for you.

Fewww … Now i know at least a work-around for this error, it will save me from a lot of headaches later.

If you could post your result here, then i am very appreciated :-)

Update: Updating DNE solves the problem indeed (uninstall VPN, get the latest DNE driver at deterministicnetworks.com, install it and then install VPN again). Deterministic Networks was acquired by Citrix, it’s site is redirected to Citrix’s

Update: If you happen to use the latest version (5.0.04.0300, as of Nov 2nd 2008) and still have this 442 error, uninstall the client and use an older version e.g. 5.0.03.0560

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Comments 13

  1. Chris wrote:

    The problem exists with MS Network Monitor and Vista. However, simply uninstalling NetMon will not solve the problem. Before uninstalling NetMon, run “nmconfig /uninstall” from the directory the application is installed. Once this is done you can uninstall Network Monitor. Reboot your system and all is right in the world!

    Posted 16 Jan 2008 at 3:14 am
  2. Cisco wrote:

    Thanks for post. It`s help me in job. Sorry for my bad english :)

    Posted 21 Feb 2008 at 1:19 pm
  3. Mark wrote:

    Excellent solution! Make sure that you first completely uninstall from the Control Panel - then do a restart! before installing “as administrator” Do not skip the restart.

    Posted 05 Apr 2008 at 8:11 pm
  4. Joe wrote:

    The link to the latest driver on deterministicnetworks.com has a message saying their products are retired from commerical sale. How can one get the latest driver?

    Posted 25 Apr 2008 at 6:51 pm
  5. Lamnk wrote:

    There is a link to “DNE Support” at the top left corner:

    http://www.deterministicnetworks.com/support/dnesupport.asp

    Posted 27 Apr 2008 at 10:05 am
  6. J0M0 wrote:

    Thanks for the direction.
    The following procedure worked perfectly for me.

    -Uninstall VPN client.
    -Restart
    -Install DNE Update.
    -Restart
    -Log on as administrator
    -Install VPN client (Right click “run as admin”)
    -Restart
    -Log in as standard user
    -Open VPN client
    -Open task manager
    -Click “show process from all users”
    -Set both cvpnd.exe and vpngui.exe for XP SP2 Compadibility mode, and check the “run as administrator” box
    -Restart

    You will have to clic the UAC prompt when starting windows, and when opening the client UI. But it finally works!!!!!

    This working setup is on a Vista Enterprise SP1 and Cisco VPN Client v5.0.03.0530.

    Hope it helps!

    Posted 18 May 2008 at 5:02 pm
  7. Lamnk wrote:

    Thank you for the guide, Jomo.

    Posted 20 May 2008 at 10:04 pm
  8. JoMo wrote:

    I just want to add one quick not. If you still have issues after trying the above workarounds. Try installing ccleaner (free) to clean your registry. Also use it to make sure the VPN client doesn’t start along with windows.

    I haven’t had a single problem since I used ccleaner. Hope this helps someone…

    Posted 07 Jun 2008 at 1:26 am
  9. Tim wrote:

    I had this same problem start out of nowhere. After coming to this site and seeing some of the fixes, all I did was open C:\Program Files\Cisco Systems\VPN Client, right clicked on ipsecdialer.exe and vpngui.exe and clicked properties. I set both to run in xpSP2 compatibility mode and run as administrator. Problem was immediately fixed, no reinstallation was necessary and no DNE update was necessary. But yes I have to agree to let it run each time I start it.

    Posted 21 Aug 2008 at 11:08 pm
  10. John Bryntze wrote:

    Thanks for the ideas, I have an KB article with some other ideas how to solve this problem:
    http://john.bryntze.net/jbkb/index.php?title=Vista-kb18_Cisco_VPN_%22Reason_442:_Failed_to_enable_Virtual_Adapter%22

    Posted 02 Sep 2008 at 8:46 pm
  11. Hans Nierop wrote:

    I have try al the things but nothing helps. At least I try the solution of Tim (9) and now it works! I work with Vista. Thanks!

    Posted 07 Sep 2008 at 2:31 pm
  12. Roger B wrote:

    I found the answer. Log in as administrator, and remove and reinstall as administrator. On Vista you need to enbale adminintrator account. There is info on the web how to do that.

    Posted 13 Sep 2008 at 11:20 pm
  13. Mukundi A wrote:

    This fixed my problem — download and install the latest version of DNE then restart and open vpnclient. If it does not work reinstall the vpnclient.

    http://www.deterministicnetworks.com/Downloads/dneupdate.asp

    Posted 02 Oct 2008 at 9:31 pm

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