diff --git a/cmd/sbox/sbox.go b/cmd/sbox/sbox.go
index 6459ea1..f3931a4 100644
--- a/cmd/sbox/sbox.go
+++ b/cmd/sbox/sbox.go
@@ -275,7 +275,10 @@
 			if !state.Inherit {
 				return nil, fmt.Errorf("Can't have inherit set to false")
 			}
-			env = append(env, *envVar.Name+"="+os.Getenv(*envVar.Name))
+			val, ok := os.LookupEnv(*envVar.Name)
+			if ok {
+				env = append(env, *envVar.Name+"="+val)
+			}
 		default:
 			return nil, fmt.Errorf("Unhandled state type")
 		}