Troubleshooting Tip: 'Installed firmware is not signed by Fortinet' error

[iskandar_lie]

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 Version: FortiGate-VM64-AZURE v7.0.9,build0444,221121 (GA.M) Firmware Signature: un-certified Virus-DB: 1.00000(2018-04-09 18:07) 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 Technical Tip: Installing firmware from system reboot FortiOS image signing and verification