Java Application Blocked: missing a "Permissions" manifest attribute in the main jar

When launching a client or the designer:

This has to do with having a version of Java that is too new and a version of Ignition that is too old.

This error will occur with versions of Java higher than 7u25 and versions of Ignition lower than 7.5.11 and 7.6.4

Either roll back Java to Java 7u25 or upgrade Ignition to 7.5.12+ or 7.6.7, depending on what version you currently have installed. Archived downloads can be found on this page.