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The necessary VPN Subsystem is not available.

Hi all,

I have installed CISCO VPN V3.5. Now when I use VPN Dialer after restarting the PC, I get the following error message.

"The necessary VPN Subsystem is not available. You will not be able to make connection to the remote IPSEC server."

Kindly give your suggestions / solutions.

Thanks & Regards,

-Gnana Shekar-

New Member

Re: The necessary VPN Subsystem is not available.

What is the platform you are using ? Windows2000 or NT ?

Make sure you have administrator privilege to do the installation.

Trying to run the VPN client returns the following error.

"The necessary VPN sub-system is not available. You will not be able to make a connection to the remote IPSec server."

This may be due to a problem during the installation of the client where is exited prematurely without error. As a result some of the necessary VPN client services/drivers do not get started after rebooting.

To see if you have this problem, perform the following steps:

1. Uninstall the VPN client, restart the PC.

2. Look in the Startup group for the following shortcut.

c:\Documents and Setting\All users\Start Menu\Programs\Startup\Cisco Systems VPN Client.lnk

3. If the link exists, delete it and reinstall the client. Reinstalling should

now fully complete the client install and it should run properly.

Try above steps see any help.

Best Regards,

New Member

Re: The necessary VPN Subsystem is not available.

Hi ,

Before you try to re-install the VPN iwould suggest you to check if the

Cisco VPN service is runnning . You can check this from the services.

Thanks and reagrds,

goutham bharadwaj

New Member

Re: The necessary VPN Subsystem is not available.


I had done a reinstall of the VPN client and experienced the same thing. I think this fix will work for anyone, particularly those users who had previous VPN client installations.

The problem seems to lie in the following registry key (folder):


On a reinstall or uninstall, that key folder is left, but the values are changed and, oddly enough, you cannot delete or edit the key or its folders via RegEdit. It would appear the key gets totally munged somehow in the process.

If you go to or some other shareware repository you can search on "registry" and come up with any number of utilities for restoring your Registry to a previous copy. The one I picked allowed me to restore the registry to the way it was just previous to installing the client.

Once I had the registry restored I reinstalled the software and it worked flawlessly. The visual difference was this:

1) Hardware Installation Warning for Unsigned Drivers - if you see this and have to hit continue a few times, it will work.

2) If you don't see it, your installation is corrupted.


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