diff --git a/setup/installer/windows/freeze.py b/setup/installer/windows/freeze.py
index fda8fad051..84665179e1 100644
--- a/setup/installer/windows/freeze.py
+++ b/setup/installer/windows/freeze.py
@@ -575,7 +575,7 @@ class Win32Freeze(Command, WixMixIn):
         dll = self.j(self.obj_dir, 'calibre-launcher.dll')
         ver = '.'.join(__version__.split('.')[:2])
         if self.newer(dll, objects):
-            cmd = [msvc.linker, '/DLL', '/VERSION:'+ver, '/OUT:'+dll,
+            cmd = [msvc.linker, '/DLL', '/VERSION:'+ver, '/LTCG', '/OUT:'+dll,
                    '/nologo', '/MACHINE:'+machine] + dlflags + objects + \
                 [self.embed_resources(dll),
                 '/LIBPATH:%s/libs'%self.python_base,
@@ -605,10 +605,10 @@ class Win32Freeze(Command, WixMixIn):
                     self.run_builder(cmd)
                 exe = self.j(self.base, bname+'.exe')
                 lib = dll.replace('.dll', '.lib')
-                u32 = ['user32.lib'] if typ == 'gui' else []
+                u32 = ['user32.lib']
                 if self.newer(exe, [dest, lib, self.rc_template, __file__]):
                     self.info('Linking', bname)
-                    cmd = [msvc.linker] + ['/MACHINE:'+machine,
+                    cmd = [msvc.linker] + ['/MACHINE:'+machine, '/LTCG',
                             '/LIBPATH:'+self.obj_dir, '/SUBSYSTEM:'+subsys,
                             '/LIBPATH:%s/libs'%self.python_base, '/RELEASE',
                             '/OUT:'+exe] + u32 + dlflags + [self.embed_resources(exe),
diff --git a/setup/installer/windows/main.c b/setup/installer/windows/main.c
index e2abedba02..8e0b5bdc90 100644
--- a/setup/installer/windows/main.c
+++ b/setup/installer/windows/main.c
@@ -5,24 +5,28 @@
 #define UNICODE
 #define WINDOWS_LEAN_AND_MEAN
 #include<windows.h>
-#include<stdio.h>
+#include<strsafe.h>
+
+size_t mystrlen(const wchar_t *buf) {
+    size_t ans = 0;
+    if (FAILED(StringCbLengthW(buf, 500, &ans))) return 0;
+    return ans;
+}
 
 static int show_error(const wchar_t *preamble, const wchar_t *msg, const int code) {
     wchar_t *buf;
     buf = (wchar_t*)LocalAlloc(LMEM_ZEROINIT, sizeof(wchar_t)*
-            (wcslen(msg) + wcslen(preamble) + 80));
+            (mystrlen(msg) + mystrlen(preamble) + 80));
+    if (!buf) {
+        MessageBox(NULL, preamble, NULL, MB_OK|MB_ICONERROR);
+        return code;
+    }
 
-    _snwprintf_s(buf, 
-        LocalSize(buf) / sizeof(wchar_t), _TRUNCATE,
-        L"%s\r\n  %s (Error Code: %d)\r\n", 
-        preamble, msg, code);
-
-#ifdef GUI_APP
     MessageBeep(MB_ICONERROR);
-    MessageBox(NULL, buf, NULL, MB_OK|MB_ICONERROR);
-#else
-    wprintf_s(L"%s\n", buf);
-#endif
+    if (FAILED(StringCbPrintfW(buf, LocalSize(buf), L"%s\r\n  %s (Error Code: %d)\r\n", preamble, msg, code)))
+        MessageBox(NULL, preamble, NULL, MB_OK|MB_ICONERROR);
+    else
+        MessageBox(NULL, buf, NULL, MB_OK|MB_ICONERROR);
     LocalFree(buf);
     return code;
 }