The event state describes where in the life cycle the event is.

Table 1. Event states
State Description
Ready

The system created the event and it is in the queue waiting to be processed.
Processed

The event successfully ran. An event does not necessarily trigger any further action when processed. Additional functionality must make use of the event.
Error

The event encountered an error during processing. This state is often caused by invalid event parameters. Reprocessing the event may resolve the error.
Transferred

The event was rotated to a different shard of the Event [sysevent] table. When an event is rotated, a duplicate record is created in an active shard to be processed. A scheduled job processes the event when it is next in the queue, but it is not possible to predict when this will happen as because several events may need to be processed before it. Therefore, you can reprocess the event. See Reprocess an event.