diff --git a/sim_disk.c b/sim_disk.c
index ad88d26e..3874cbce 100644
--- a/sim_disk.c
+++ b/sim_disk.c
@@ -2337,7 +2337,7 @@ Handle = CreateFileA (tmpname, DesiredAccess, FILE_SHARE_READ|FILE_SHARE_WRITE,
 free (tmpname);
 if (Handle != INVALID_HANDLE_VALUE) {
     if ((sim_os_disk_info_raw ((FILE *)Handle, NULL, NULL, &is_cdrom)) || 
-        (DesiredAccess & GENERIC_WRITE) && is_cdrom) {
+        ((DesiredAccess & GENERIC_WRITE) && is_cdrom)) {
         CloseHandle (Handle);
         errno = EACCES;
         return NULL;