Performing a Recovery Installation

If the router's software is corrupted or otherwise damaged, you may need to perform a recovery installation, using the emergency boot disk to restore the default factory installation. Once you have recovered the software you will need to restore the router’s configuration. You can either create a new configuration as you did when the router was shipped from the factory, or if you saved the router's previous configuration, you can simply restore that file to the system.

Depending on the situation, you should try to perform the following steps before you perform the recovery installation:

1. Ensure you have an emergency recovery disk to use during the installation. When the router is first shipped, an emergency recovery disk is provided with it. For instructions on creating an emergency boot disk, see Creating an Emergency Boot Disk
2. Copy the existing configuration in the file /config/juniper.conf.gz from the router to a remote system. For extra safety, you can also copy the backup configurations (the files named /config/juniper.conf.n, where n is a number from 0 through 9).

   Warning: The recovery installation process completely overwrites the entire contents of the fixed storage media.

3. Copy any other stored files to a remote system as desired.

To reinstall the Junos OS:

1. Insert the removable media into the router.

   Note: You can store a configuration on installation media such as a PC Card.

2. Reboot the router. Do not power off the router if it is already on. Issue the CLI request system reboot command.
3. When the software prompts you with the following question, type y:

   WARNING: The installation will erase the contents of your disk. Do you wish to continue (y/n)? y

4. The router copies the software from the removable media onto your system, occasionally displaying status messages. Copying the software can take up to 10 minutes.
5. Remove the removable media when prompted. The router then reboots from the boot device on which the software was just installed. When the reboot is complete, the router displays the login prompt.
6. Create a new configuration as you did when the router was shipped from the factory, or restore a previously saved configuration file to the system. For more information, see Creating a New Configuration on a Single Routing Engine, Creating a New Configuration with Redundant Routing Engines, and Restoring a Saved Configuration.