Upgrading FortiAuthenticator firmware by interrupting the FortiAuthenticator boot process and installing a firmware image from a TFTP server erases the current FortiAuthenticator configuration and replaces it with factory default settings.
Fortinet recommends setting your monitor to a screen resolution of 1600x1200. This allows for all the objects in the GUI to be viewed properly without the need for scrolling.
Save a copy of your FortiAuthenticator configuration before upgrading the firmware. Go to System > Dashboard > Status and select Backup/Restore > Download Backup File to backup the configuration.
Clear your browser cache before logging in to the FortiAuthenticator GUI to ensure the pages display properly.