diff --git a/headers/os/app/Roster.h b/headers/os/app/Roster.h
index 8b3b664ca0..50a6612b0e 100644
--- a/headers/os/app/Roster.h
+++ b/headers/os/app/Roster.h
@@ -1,9 +1,6 @@
 /*
- * Copyright 2001-2007, Haiku.
+ * Copyright 2001-2009, Haiku, Inc.
  * Distributed under the terms of the MIT License.
- *
- * Authors:
- *		Ingo Weinhold (bonefish@users.sf.net)
  */
 #ifndef _ROSTER_H
 #define _ROSTER_H
@@ -166,7 +163,9 @@ class BRoster {
 		status_t _SendToRunning(team_id team, int argc, const char *const *args,
 					const BList *messageList, const entry_ref *ref,
 					bool readyToRun) const;
-		void _InitMessengers();
+		void _InitMessenger();
+		static status_t _InitMimeMessenger(void* data);
+		BMessenger& _MimeMessenger();
 		void _AddToRecentApps(const char *appSig) const;
 		void _ClearRecentDocuments() const;
 		void _ClearRecentFolders() const;
@@ -176,7 +175,8 @@ class BRoster {
 
 		BMessenger	fMessenger;
 		BMessenger	fMimeMessenger;
-		uint32		_reserved[3];
+		int32		fMimeMessengerInitOnce;
+		uint32		_reserved[2];
 };
 
 // global BRoster instance
diff --git a/src/kits/app/Roster.cpp b/src/kits/app/Roster.cpp
index 1c2f6bb6da..3d7df462ed 100644
--- a/src/kits/app/Roster.cpp
+++ b/src/kits/app/Roster.cpp
@@ -1,9 +1,9 @@
 /*
- * Copyright 2001-2009, Haiku.
+ * Copyright 2001-2009, Haiku, Inc.
  * Distributed under the terms of the MIT License.
  *
  * Authors:
- *		Ingo Weinhold (bonefish@users.sf.net)
+ *		Ingo Weinhold (ingo_weinhold@gmx.de)
  *		Axel Dörfler, axeld@pinc-software.de
  */
 
@@ -42,6 +42,8 @@
 #include <Volume.h>
 #include <VolumeRoster.h>
 
+#include <locks.h>
+
 #include <AppMisc.h>
 #include <DesktopLink.h>
 #include <MessengerPrivate.h>
@@ -534,9 +536,10 @@ BRoster::ArgVector::Unset()
 BRoster::BRoster()
 	:
 	fMessenger(),
-	fMimeMessenger()
+	fMimeMessenger(),
+	fMimeMessengerInitOnce(INIT_ONCE_UNINITIALIZED)
 {
-	_InitMessengers();
+	_InitMessenger();
 }
 
 
@@ -2769,7 +2772,7 @@ BRoster::_SendToRunning(team_id team, int argc, const char* const* args,
 
 
 void
-BRoster::_InitMessengers()
+BRoster::_InitMessenger()
 {
 	DBG(OUT("BRoster::InitMessengers()\n"));
 
@@ -2781,29 +2784,46 @@ BRoster::_InitMessengers()
 
 		BMessenger::Private(fMessenger).SetTo(info.team, rosterPort,
 			B_PREFERRED_TOKEN);
-
-		// ask for the MIME messenger
-		// Generous 1s + 5s timeouts. It could actually be synchronous, but
-		// timeouts allow us to debug the registrar main thread.
-		BMessage request(B_REG_GET_MIME_MESSENGER);
-		BMessage reply;
-		status_t error = fMessenger.SendMessage(&request, &reply, 1000000LL,
-			5000000LL);
-		if (error == B_OK && reply.what == B_REG_SUCCESS) {
-			DBG(OUT("  got reply from roster\n"));
-				reply.FindMessenger("messenger", &fMimeMessenger);
-		} else {
-			DBG(OUT("  no (useful) reply from roster: error: %lx: %s\n", error,
-				strerror(error)));
-			if (error == B_OK)
-				DBG(reply.PrintToStream());
-			fMessenger = BMessenger();
-		}
 	}
+
 	DBG(OUT("BRoster::InitMessengers() done\n"));
 }
 
 
+/*static*/ status_t
+BRoster::_InitMimeMessenger(void* data)
+{
+	BRoster* roster = (BRoster*)data;
+
+	// ask for the MIME messenger
+	// Generous 1s + 5s timeouts. It could actually be synchronous, but
+	// timeouts allow us to debug the registrar main thread.
+	BMessage request(B_REG_GET_MIME_MESSENGER);
+	BMessage reply;
+	status_t error = roster->fMessenger.SendMessage(&request, &reply, 1000000LL,
+		5000000LL);
+	if (error == B_OK && reply.what == B_REG_SUCCESS) {
+		DBG(OUT("  got reply from roster\n"));
+			reply.FindMessenger("messenger", &roster->fMimeMessenger);
+	} else {
+		DBG(OUT("  no (useful) reply from roster: error: %lx: %s\n", error,
+			strerror(error)));
+		if (error == B_OK)
+			DBG(reply.PrintToStream());
+	}
+
+	return error;
+}
+
+
+BMessenger&
+BRoster::_MimeMessenger()
+{
+	__init_once(&fMimeMessengerInitOnce, &_InitMimeMessenger, this);
+	return fMimeMessenger;
+}
+
+
 /*! \brief Sends a request to the roster to add the application with the
 	given signature to the front of the recent apps list.
 */
diff --git a/src/kits/app/RosterPrivate.cpp b/src/kits/app/RosterPrivate.cpp
index 3e8d9bff5c..06f730c540 100644
--- a/src/kits/app/RosterPrivate.cpp
+++ b/src/kits/app/RosterPrivate.cpp
@@ -11,8 +11,11 @@
 
 
 #include <RosterPrivate.h>
+
 #include <Roster.h>
 
+#include <locks.h>
+
 
 /*!	\class BRoster::Private
 	\brief Class used to access private BRoster members.
@@ -32,6 +35,7 @@ BRoster::Private::SetTo(BMessenger mainMessenger, BMessenger mimeMessenger)
 	if (fRoster != NULL) {
 		fRoster->fMessenger = mainMessenger;
 		fRoster->fMimeMessenger = mimeMessenger;
+		fRoster->fMimeMessengerInitOnce = INIT_ONCE_INITIALIZED;
 	}
 }
 
@@ -62,7 +66,7 @@ BRoster::Private::SendTo(BMessage *message, BMessage *reply, bool mime)
 		return B_NO_INIT;
 
 	if (mime)
-		return fRoster->fMimeMessenger.SendMessage(message, reply);
+		return fRoster->_MimeMessenger().SendMessage(message, reply);
 
 	return fRoster->fMessenger.SendMessage(message, reply);
 }
@@ -80,7 +84,7 @@ BRoster::Private::SendTo(BMessage *message, BMessage *reply, bool mime)
 bool
 BRoster::Private::IsMessengerValid(bool mime) const
 {
-	return fRoster != NULL && (mime ? fRoster->fMimeMessenger.IsValid()
+	return fRoster != NULL && (mime ? fRoster->_MimeMessenger().IsValid()
 		: fRoster->fMessenger.IsValid());
 }