diff --git a/programs/winecfg/drive.c b/programs/winecfg/drive.c
index bee5be3af34..b4b4239c003 100644
--- a/programs/winecfg/drive.c
+++ b/programs/winecfg/drive.c
@@ -140,7 +140,7 @@ static DWORD get_drive_type( char letter )
     else
     {
         WCHAR buffer[80];
-        DWORD size = ARRAY_SIZE(buffer);
+        DWORD size = sizeof(buffer);
 
         if (!RegQueryValueExW( hKey, driveValue, NULL, NULL, (LPBYTE)buffer, &size ))
         {