Netscaler: Logon to GUI error ‘Invalid Argument [ns]’ after upgrading NetScaler

Today I have updated an NetScaler HA pair to the latest version. The NetScalers are using a custom made theme. After upgrading the HA pair management access trough the GUI was not possible anymore. The NetScaler showed the ‘Invalid argument [ns]’ error.


As a quick fix it is possible to copy the default admin GUI to the running config. The copy must be done by accessing the NetScaler shell. After accessing the shell the copy can be done with the following command:

  • # cp -r /var/netscaler/gui/admin_ui  /var/ns_gui_custom/ns_gui/


Be aware that is only a temporary fix, the configuration will be lost after a reboot. To fix this permanently you have to rebuild the custom made theme. Before proceeding, check if all functionality works on the NetScaler.

If everything’s working, then we can create the customtheme.tar.gz again so that it persists across config change or reboots. This can be done with the following commands:

  • # cd /var/ns_gui_custom/
  • # tar -cvzf customtheme.tar.gz ns_gui/*