There are four known issues that can cause the following error when attempting to start the Ignition service:
Ignition is Pointing to the Wrong Version of Java
This can happen if Java was upgraded and Ignition is still pointing to the wrong java path.
To fix this, change the java path in the ignition.conf file. The process is described in the article here.
Restoring a Backup from a Future Version
While Ignition is certainly backwards compatible, it is unfortunately not forward compatible. For example, you are able to restore a 7.5.12 backup or project into a 7.7.1 gateway, but not vice versa.
To use this backup, upgrade your gateway to either the same version the backup was taken from, or a newer version. If you are unsure of whether or not your license is eligible for an upgrade, please contact your Account Executive at Inductive Automation.
Due to the issue discussed above, running the installer of an earlier version in order to downgrade will result in the same error.
The process for downgrading Ignition can be found here.
Enhanced Mitigation Experience Toolkit (EMET) is Installed
The Ignition Gateway Service will not start when the Enhanced Mitigation Experience Toolkit (EMET) is installed. Attempting to start the Ignition Service will give the above stated errors.
It has been found that the Enhanced Mitigation Experience Toolkit (EMET) is the root cause of this problem. This software was released by Microsoft and you can find additional information about it here.The default settings of this application will prevent the Ignition Service from starting. Uninstalling EMET will resolve this issue.