| Description | This article explains how to solve the 'Installed firmware is not signed by Fortinet' error. |
| Scope | FortiGate |
| Solution | 
This screen may appear when accessing FortiGate through HTTPS. The CLI will show a similar warning. It can happen on any FortiOS version after performing an upgrade.
A system status check of the CLI shows the firmware is un-certified:
FGT # get system status
This happens when an image verification fails during image upgrade and is cached.
This warning can be left as-is until the next upgrade. It will not affect performance or device operations. To resolve the issue, re-flash the affected device. Manually download and verify the OS image from this page: https://support.fortinet.com/Download/FirmwareImages.aspx
Relevant documentation: Technical Tip: How to upgrade the FortiGate firmwa... - Fortinet Community Technical Tip: FortiGate HA upgrade procedure and ... - Fortinet Community Technical Tip: Rebuilding an HA cluster |
