diff --git a/classes/Mission.m b/classes/Mission.m
index fe5590fdb0470d960e63bb9a9ca38f5b4d115714..825d8d38bd681847694871f51cd5d24298beac38 100644
--- a/classes/Mission.m
+++ b/classes/Mission.m
@@ -32,7 +32,7 @@ classdef Mission < Config
                 m {mustBeA(m, {'logical', 'string', 'char'})} = false
             end
 
-            if ~m, return; end
+            if ~isa(m, 'string') && isempty(m), return; end
 
             filePath = fullfile(fileparts(mfilename("fullpath")), '..', 'missions');
             filePath = trimPath(filePath);