diff --git a/dlls/msi/registry.c b/dlls/msi/registry.c
index 1bee58d8e4..daa01e3e51 100644
--- a/dlls/msi/registry.c
+++ b/dlls/msi/registry.c
@@ -1284,6 +1284,9 @@ UINT WINAPI MsiEnumClientsA(LPCSTR szComponent, DWORD index, LPSTR szProduct)
 
     TRACE("%s %d %p\n", debugstr_a(szComponent), index, szProduct);
 
+    if ( !szProduct )
+        return ERROR_INVALID_PARAMETER;
+
     if( szComponent )
     {
         szwComponent = strdupAtoW( szComponent );
@@ -1311,7 +1314,7 @@ UINT WINAPI MsiEnumClientsW(LPCWSTR szComponent, DWORD index, LPWSTR szProduct)
 
     TRACE("%s %d %p\n", debugstr_w(szComponent), index, szProduct);
 
-    if (!szComponent || !szProduct)
+    if (!szComponent || !*szComponent || !szProduct)
         return ERROR_INVALID_PARAMETER;
 
     r = MSIREG_OpenComponentsKey(szComponent,&hkeyComp,FALSE);
diff --git a/dlls/msi/tests/msi.c b/dlls/msi/tests/msi.c
index e98788462d..61c7ddfd9d 100644
--- a/dlls/msi/tests/msi.c
+++ b/dlls/msi/tests/msi.c
@@ -1618,18 +1618,12 @@ static void test_MsiEnumClients(void)
     /* empty szComponent */
     product[0] = '\0';
     r = MsiEnumClientsA("", 0, product);
-    todo_wine
-    {
-        ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_INVALID_PARAMETER, got %d\n", r);
-    }
+    ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_INVALID_PARAMETER, got %d\n", r);
     ok(!lstrcmpA(product, ""), "Expected product to be unchanged, got %s\n", product);
 
     /* NULL lpProductBuf */
     r = MsiEnumClientsA(component, 0, NULL);
-    todo_wine
-    {
-        ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_INVALID_PARAMETER, got %d\n", r);
-    }
+    ok(r == ERROR_INVALID_PARAMETER, "Expected ERROR_INVALID_PARAMETER, got %d\n", r);
 
     /* all params correct, component missing */
     product[0] = '\0';