When a license expires on a NetScaler appliance, many features become disabled. After installing a new license, you may notice that a significant portion of the configuration is missing - such as SSL certificates, Application Firewall (AppFw) settings, and other feature-specific configurations.

The `save config` command may have been executed while the appliance was in an unlicensed state. In this state, many configuration settings are not applied. As a result, running `save config` at that time would save the incomplete configuration and replace the valid one. When the system later reloads, problematic configuration is loaded, causing the current configuration to be lost or corrupted.

It is strongly advised not to execute the `save config` command when the appliance is in an unexpected or transitional state (e.g., unlicensed). Doing so may result in saving an incomplete configuration.

If the issue has already occurred, restore a previous configuration file (such as ns.conf.3,  which is a good one) to recover the system’s settings.

> shell
root@ns# cd /nsconfig
root@ns# cp ns.conf.3 ns.conf.3.good.bak       // In case of this round recovery does not work and future `save config` rotates it.
root@ns# mv ns.conf ns.conf.bad.bak
root@ns# mv ns.conf.3 ns.conf
root@ns# reboot

This article describes a config missing isssue after reapplying license.