diff --git a/configure-pre.in b/configure-pre.in
index 9f0d2f29..e4f66a54 100644
--- a/configure-pre.in
+++ b/configure-pre.in
@@ -235,8 +235,19 @@ if test $enable_gui == "moblin"; then
     AC_DEFINE(USE_MOBLIN_UX, 1, [Use the MUX widget library])
 fi
 
+
 if test $enable_gui != "no"; then
-    PKG_CHECK_MODULES(GUI, glib-2.0 dbus-glib-1 >= 0.60 gtk+-2.0 libglade-2.0 gconf-2.0 gio-2.0 unique-1.0)
+    gui_modules="glib-2.0 dbus-glib-1 >= 0.60 gtk+-2.0 libglade-2.0 gconf-2.0 gio-2.0"
+
+    PKG_CHECK_MODULES(UNIQUE, unique-1.0,
+                      have_unique="yes",
+                      have_unique="no")
+    if test $have_unique == "yes"; then
+        gui_modules="$gui_modules unique-1.0" 
+        AC_DEFINE(ENABLE_UNIQUE, 1, [enable single-app-instance functionality])
+    fi
+    PKG_CHECK_MODULES(GUI, $gui_modules)
+
     AC_PATH_PROG([GTK_BUILDER_CONV], gtk-builder-convert)
     IT_PROG_INTLTOOL([0.37.1])
     GETTEXT_PACKAGE=syncevolution
diff --git a/src/gtk-ui/main.c b/src/gtk-ui/main.c
index f94338b3..3d4166bf 100644
--- a/src/gtk-ui/main.c
+++ b/src/gtk-ui/main.c
@@ -19,11 +19,14 @@
 
 #include <gtk/gtk.h>
 #include <glib/gi18n.h>
-#include <unique/unique.h>
 
 #include "config.h"
 #include "sync-ui.h"
 
+#ifdef ENABLE_UNIQUE
+
+#include <unique/unique.h>
+
 enum
 {
     COMMAND_0, 
@@ -95,3 +98,21 @@ main (int argc, char *argv[])
     g_object_unref (app);
     return 0;
 }
+
+#else
+
+int
+main (int argc, char *argv[])
+{
+    gtk_init (&argc, &argv);
+    bindtextdomain (GETTEXT_PACKAGE, SYNCEVOLUTION_LOCALEDIR);
+    bind_textdomain_codeset (GETTEXT_PACKAGE, "UTF-8");
+    textdomain (GETTEXT_PACKAGE);
+
+    sync_ui_create_main_window ();
+    gtk_main ();
+    return 0;
+}
+
+#endif /* ENABLE_UNIQUE */
+