diff --git a/ChangeLog b/ChangeLog
index 003d66d926..6d60b2dc71 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Apr 23 01:47:54 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* win32/win32.c (rb_w32_wopen): shouldn't use FILE_FLAG_OVERLAPPED with
+	  normal file.  #1807, #2510, #2549
+
 Fri Apr 23 01:28:03 2010  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* thread_win32.c (ubf_handle): remove unused typedef.
diff --git a/win32/win32.c b/win32/win32.c
index 70b49769a2..26477e86be 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -4684,9 +4684,6 @@ rb_w32_wopen(const WCHAR *file, int oflag, ...)
 	_set_osfhnd(fd, (long)INVALID_HANDLE_VALUE);
 	_set_osflags(fd, 0);
 
-	/* open with FILE_FLAG_OVERLAPPED if have CancelIo */
-	if (cancel_io)
-	    attr |= FILE_FLAG_OVERLAPPED;
 	h = CreateFileW(file, access, FILE_SHARE_READ | FILE_SHARE_WRITE, &sec,
 			create, attr, NULL);
 	if (h == INVALID_HANDLE_VALUE) {