FinalBuilder reads in the system's Environment variables when it starts. These can be used in the same manner as Project variables. Setting an Environment variable can only be done during a run, either with the Set Variable Action or in the Action Script events.
The values assigned to Environment variables by FinalBuilder during a run are not saved after a run. FinalBuilder sets them temporarily and then restores them to their original values at the end of the run.
Environment variables in FinalBuilder are also made available to applications that it executes.
If you modify an Environment variable outside of FinalBuilder, FinalBuilder will not see this change until you restart FinalBuilder.