'Installed firmware is not signed by Fortinet' error

[martyyy]

When we logon to the unit we receive an error that the Firmware was not signed by Fortinet. This was after an upgrade to FortiOS 7.2.7.

The previous FortiOS version is 7.0.12 the resolution for this is to update on 7.0.13 and the error message still appears and now we upgrade it to FortiOS 7.2.7 still having the error message.

The unit is part of a HA cluster. The second unit of the cluster does not have the error.

Any workaround or recommendation would highly appreciated.

[hjezzapaula · Accepted solution]

Hi, 

You may check on below KB to resolve this error

https://community.fortinet.com/t5/FortiGate/Troubleshooting-Tip-Installed-firmware-is-not-signed-by-...

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