Skip to end of metadata
Go to start of metadata


    This document describes procedures to be followed in case of problems during the installation or uninstallation of the LANCOM Advanced VPN Client for Windows (version 3.0 or later).



    1) Installation of version 3.0 of the client fails

    A failure and roll-back of the installation process is usually caused by a conflict detected during the installation of the NCP filter driver in the operating system. This can have a number of different reasons, the following in particular:

    The installation of the filter driver is prevented by third-party software. Particularly security software, such as firewalls, anti-virus software, or other VPN clients on the system, can prevent the installation of additional filter drivers. Known problems exist with certain versions of Kaspersky and Symantec anti-virus software.

    These products must be completely removed from the system in order to install the LANCOM Advanced VPN Client. It is not sufficient to stop the services! After the installation, the anti-virus software can be re-installed on the system.

    To narrow down the cause of the problem, you need some information about the affected computer:

      1.1) Inspecting the MSI installation log

      The following command that starts the installer causes an installation log file to be created:

      Name_of_installer.exe /v" /log "%USERPROFILE%\ncp_log.txt""

      The generated log file can then be checked for the following entries:

      DIFXAPP: ERROR: Error 0x80070005 encountered while installing the inf 'C:\Windows\system32\DRVSTORE\ncpfilt_F18FBEB9487961CB9E977A80A05C5149CA2BD704\ncpfilt.inf'. Unable to install network component '*ncpfilt'

      DIFXAPP: ERROR: Failed to install the network driver INF C:\Windows\system32\DRVSTORE\ncpfilt_F18FBEB9487961CB9E977A80A05C5149CA2BD704\ncpfilt.inf. Error code 0x643

      You will find these entries if the installation of the filter driver failed.

      1.2) Inspecting driver-related information

      The following registry keys should be inspected if possible:


      HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\Root => enumroot.reg

      Additional information about the driver installation can be found in the Microsoft driver log files:


      1.3) Removing driver files manually

      This section is only relevant if a version 3.0 VPN client was already installed on the system prior to the current installation and the information listed above has already been checked.

      It is highly advisable not to delete registry entries or files/folders manually outside the scope of these instructions!

      Check the folder C:\Windows\inf for oem*.inf files. Then search these files for the strings *rwsgap and *ncpfilt . If you find these files on the system, they should be removed as follows:
      • Open a command line window with administrator rights.
      • Navigate to the folder C:\Windows (e.g. cd \windows).
      • Remove the found oem<X>.inf files with the command pnputil –d oem<X>.inf (e.g. pnputil –d oem74.inf).
      • If a file cannot be removed with the Windows tool PnpUtil, delete the oem<X>.inf file including the corresponding oem<X>.pnf. (e.g. del c:\windows\inf\oem74.inf and del c:\windows\inf\oem74.pnf)
      • Afterwards, search the folder c:\windows\system32\drivers for the file ncplelhp.sys and delete this as well. (e.g. del c:\windows\system32\drivers\ncplelhp.sys)
      • Open the registry and delete the following entry (if it exists) => [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ncplelhp]
      • Reboot the system and try to install the client again.

    2) The version 3.0 VPN client cannot be uninstalled

    In this scenario, the update of the client to version 3.0 runs flawlessly, but the updated VPN client does not work and cannot be uninstalled, either.

    This is usually caused by a mistake made during the update:

    1) Start the version 3.0 installer.
    2) The user is prompted to uninstall the existing client (e.g. version 2.32).
    3) The uninstall is performed.
    4) The user does not reboot the system in spite of being requested to do so.
    5) The version 3.0 installer is started.
    6) The system is rebooted.

    Due to the omitted reboot after uninstalling the old version, a part of the uninstall routine is still active and damages the newly installed VPN client.

    In this case, the file “ncpcfg.dll” must be manually copied into the installation folder of the client. You can obtain this file from the LANCOM Systems Support team upon request . If necessary, the folder must be created manually:

    LANCOM: C:\Program Files (x86)\LANCOM\Advanced VPN Client\ncpcfg.dll

    After rebooting the system, the client can either be uninstalled and re-installed properly, or repaired via the repair function of the installer. After rebooting once again, the client is fully operational.