diff --git a/plugins/mod_storage_internal.lua b/plugins/mod_storage_internal.lua
index 972ecbee3..ade4f0a65 100644
--- a/plugins/mod_storage_internal.lua
+++ b/plugins/mod_storage_internal.lua
@@ -6,6 +6,9 @@ local driver = {};
 local driver_mt = { __index = driver };
 
 function driver:open(store, typ)
+	if typ and typ ~= "keyval" then
+		return nil, "unsupported-store";
+	end
 	return setmetatable({ store = store, type = typ }, driver_mt);
 end
 function driver:get(user)
diff --git a/plugins/mod_storage_none.lua b/plugins/mod_storage_none.lua
index 8f2d2f560..fa925b761 100644
--- a/plugins/mod_storage_none.lua
+++ b/plugins/mod_storage_none.lua
@@ -1,8 +1,11 @@
 local driver = {};
 local driver_mt = { __index = driver };
 
-function driver:open(store)
-	return setmetatable({ store = store }, driver_mt);
+function driver:open(store, typ)
+	if typ and typ ~= "keyval" then
+		return nil, "unsupported-store";
+	end
+	return setmetatable({ store = store, type = typ }, driver_mt);
 end
 function driver:get(user)
 	return {};
diff --git a/plugins/mod_storage_sql.lua b/plugins/mod_storage_sql.lua
index 7b810ab85..a5bb5bfa5 100644
--- a/plugins/mod_storage_sql.lua
+++ b/plugins/mod_storage_sql.lua
@@ -380,10 +380,10 @@ end
 local driver = {};
 
 function driver:open(store, typ)
-	if not typ then -- default key-value store
-		return setmetatable({ store = store }, keyval_store);
+	if typ and typ ~= "keyval" then
+		return nil, "unsupported-store";
 	end
-	return nil, "unsupported-store";
+	return setmetatable({ store = store }, keyval_store);
 end
 
 function driver:stores(username)