Cisco Router not using startup-config after a reload

Warning! Out of date content.

A few days ago I started tinkering with an old Cisco 2621 router.

I made some changes to the running-config, performed a write memory to save the config and reloaded the router. When the router was running again my configuration was not active.

A more nvram:startup-config showed the configuration I created actually had been saved. It just wasn’t being used after the reload.

A show version told me:

Configuration register is 0x41

The configuration-register allows you to control the boot process. The register was set to ignore the contents of the nvram. Probably a remnant of a password recovery procedure.

I switched the configuration register back to its default setting with:

config-register 0x2102

During the next reload the router successfully loaded my startup-config.

So if you have a Cisco router ignoring the startup-config in nvram check the value of the configuration register. You can (probably) find additional info by searching for configuration-register on the Cisco.com website.