diff --git a/Applications/Games/Assassin's Creed: Brotherhood/Steam/script.json b/Applications/Games/Assassin's Creed: Brotherhood/Steam/script.json
index 978cbdce9e..4949df029b 100644
--- a/Applications/Games/Assassin's Creed: Brotherhood/Steam/script.json	
+++ b/Applications/Games/Assassin's Creed: Brotherhood/Steam/script.json	
@@ -1,6 +1,6 @@
 {
 	"scriptName": "Steam",
-	"compatibleOperatingSystems": ["LINUX"],
+	"compatibleOperatingSystems": ["MACOSX", "LINUX"],
 	"testingOperatingSystems": ["MACOSX"],
 	"free": false,
 	"requiresPatch": false
diff --git a/Applications/Games/Far Cry 3 - Blood Dragon/Uplay/script.json b/Applications/Games/Far Cry 3 - Blood Dragon/Uplay/script.json
index bae8191bdb..bd5c110a74 100644
--- a/Applications/Games/Far Cry 3 - Blood Dragon/Uplay/script.json	
+++ b/Applications/Games/Far Cry 3 - Blood Dragon/Uplay/script.json	
@@ -1,6 +1,6 @@
 {
 	"scriptName": "Uplay",
-	"compatibleOperatingSystems": [],
+	"compatibleOperatingSystems": ["LINUX"],
 	"testingOperatingSystems": ["LINUX"],
 	"free": false,
 	"requiresPatch": false
diff --git a/Applications/Games/PAYDAY The Heist/Steam/script.json b/Applications/Games/PAYDAY The Heist/Steam/script.json
index 978cbdce9e..4949df029b 100644
--- a/Applications/Games/PAYDAY The Heist/Steam/script.json	
+++ b/Applications/Games/PAYDAY The Heist/Steam/script.json	
@@ -1,6 +1,6 @@
 {
 	"scriptName": "Steam",
-	"compatibleOperatingSystems": ["LINUX"],
+	"compatibleOperatingSystems": ["MACOSX", "LINUX"],
 	"testingOperatingSystems": ["MACOSX"],
 	"free": false,
 	"requiresPatch": false
diff --git a/validate.py b/validate.py
index af35675700..403c883702 100644
--- a/validate.py
+++ b/validate.py
@@ -116,6 +116,10 @@
         with open(script_json_file) as f:
             script_json = json.loads(f.read().decode("utf-8-sig"))
             jsonschema.validate(script_json, script_schema)
+            # check that testingOperatingSystems is a subset of compatibleOperatingSystems
+            if not set(script_json['testingOperatingSystems']) <= set(script_json['compatibleOperatingSystems']):
+                print "{}: testingOperatingSystems must be a subset of compatibleOperatingSystems".format(script_json_file)
+                is_valid = False
     except ValueError as value_error:
         print "invalid script.json {}: {}".format(script_json_file, value_error)
         is_valid = False