diff --git a/mac/Build.txt b/mac/Build.txt
index 3c2cd95f0..b5f970f67 100644
--- a/mac/Build.txt
+++ b/mac/Build.txt
@@ -41,6 +41,7 @@ http://forum.audacityteam.org/viewtopic.php?p=303835#p303835 .
    patch -p0 -i <path to Audacity source>/mac/wxMac_additions/pinch-spread.patch .
    patch -p0 -i <path to Audacity source>/mac/wxMac_additions/focusrings.patch .
    patch -p0 -i <path to Audacity source>/mac/wxMac_additions/wxMac-3.0.2-wxaccessible.patch .
+   patch -p0 -i <path to Audacity source>/mac/wxMac_additions/tooldock-quit.patch .
 
 10) And finally build/install wxWidgets:
 
diff --git a/mac/wxMac_additions/tooldock-quit.patch b/mac/wxMac_additions/tooldock-quit.patch
new file mode 100644
index 000000000..e370ad76a
--- /dev/null
+++ b/mac/wxMac_additions/tooldock-quit.patch
@@ -0,0 +1,57 @@
+From 343528d045e805b84e2c4df2bacdf4d319906084 Mon Sep 17 00:00:00 2001
+From: Paul Licameli <paul.licameli@audacityteam.org>
+Date: Mon, 3 Oct 2016 13:58:26 -0400
+Subject: [PATCH] Quitting app via Mac tooldock uses events, so behavior is
+ overridable
+
+---
+ src/osx/carbon/app.cpp | 20 +++++++++++---------
+ 1 file changed, 11 insertions(+), 9 deletions(-)
+
+diff --git a/src/osx/carbon/app.cpp b/src/osx/carbon/app.cpp
+index 0926dbf..bdb78ca 100644
+--- src/osx/carbon/app.cpp
++++ src/osx/carbon/app.cpp
+@@ -259,12 +259,9 @@ short wxApp::MacHandleAEOApp(const WXEVENTREF WXUNUSED(event) , WXEVENTREF WXUNU
+ 
+ short wxApp::MacHandleAEQuit(const WXEVENTREF WXUNUSED(event) , WXEVENTREF WXUNUSED(reply))
+ {
+-    wxCloseEvent event;
+-    wxTheApp->OnQueryEndSession(event);
+-    if ( !event.GetVeto() )
++    if ( OSXOnShouldTerminate() )
+     {
+-        wxCloseEvent event;
+-        wxTheApp->OnEndSession(event);
++        OSXOnWillTerminate();
+     }
+     return noErr ;
+ }
+@@ -421,15 +418,20 @@ void wxApp::OSXOnDidFinishLaunching()
+ 
+ void wxApp::OSXOnWillTerminate()
+ {
+-    wxCloseEvent event;
++    wxCloseEvent event(wxEVT_END_SESSION, wxID_ANY);
++    event.SetEventObject(wxTheApp);
+     event.SetCanVeto(false);
+-    wxTheApp->OnEndSession(event);
++
++    wxTheApp->ProcessEvent(event);
+ }
+ 
+ bool wxApp::OSXOnShouldTerminate()
+ {
+-    wxCloseEvent event;
+-    wxTheApp->OnQueryEndSession(event);
++    wxCloseEvent event(wxEVT_QUERY_END_SESSION, wxID_ANY);
++    event.SetEventObject(wxTheApp);
++    event.SetCanVeto(true);
++
++    wxTheApp->ProcessEvent(event);
+     return !event.GetVeto();
+ }
+ #endif
+-- 
+2.3.2 (Apple Git-55)
+
diff --git a/src/AudacityApp.cpp b/src/AudacityApp.cpp
index 282afd372..47f492f97 100644
--- a/src/AudacityApp.cpp
+++ b/src/AudacityApp.cpp
@@ -744,7 +744,8 @@ void AudacityApp::MacNewFile()
 #define kAudacityAppTimerID 0
 
 BEGIN_EVENT_TABLE(AudacityApp, wxApp)
-   EVT_QUERY_END_SESSION(AudacityApp::OnEndSession)
+   EVT_QUERY_END_SESSION(AudacityApp::OnQueryEndSession)
+   EVT_END_SESSION(AudacityApp::OnEndSession)
 
    EVT_TIMER(kAudacityAppTimerID, AudacityApp::OnTimer)
 #ifdef __WXMAC__
@@ -1974,6 +1975,20 @@ void AudacityApp::FindFilesInPathList(const wxString & pattern,
    }
 }
 
+void AudacityApp::OnQueryEndSession(wxCloseEvent & event)
+{
+   bool mustVeto = false;
+
+#ifdef __WXMAC__
+   mustVeto = wxDialog::OSXHasModalDialogsOpen();
+#endif
+
+   if ( mustVeto )
+      event.Veto(true);
+   else
+      OnEndSession(event);
+}
+
 void AudacityApp::OnEndSession(wxCloseEvent & event)
 {
    bool force = !event.CanVeto();
diff --git a/src/AudacityApp.h b/src/AudacityApp.h
index 4eacac2fc..030fe7baa 100644
--- a/src/AudacityApp.h
+++ b/src/AudacityApp.h
@@ -205,6 +205,7 @@ class AudacityApp final : public wxApp {
    void OnMenuPreferences(wxCommandEvent & event);
    void OnMenuExit(wxCommandEvent & event);
 
+   void OnQueryEndSession(wxCloseEvent & event);
    void OnEndSession(wxCloseEvent & event);
 
    // Most Recently Used File support (for all platforms).