diff --git a/src/io_win.cpp b/src/io_win.cpp
index 4f6aee0..2e7ea18 100644
--- a/src/io_win.cpp
+++ b/src/io_win.cpp
@@ -87,7 +87,7 @@ int wiiuse_find(struct wiimote_t** wm, int max_wiimotes, int timeout) {
 
 		/* get the size of the data block required */
 		i = SetupDiGetDeviceInterfaceDetail(device_info, &device_data, NULL, 0, &len, NULL);
-		detail_data = malloc(len);
+		detail_data = (SP_DEVICE_INTERFACE_DETAIL_DATA_A*)malloc(len);
 		detail_data->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
 
 		/* query the data for this device */