--- a/mail/app/Makefile.in
+++ b/mail/app/Makefile.in
@@ -167,18 +167,17 @@ RCFLAGS += -DTHUNDERBIRD_ICO=\"$(DIST)/b
 endif
 
 include $(topsrcdir)/config/rules.mk
 
 ifdef MOZILLA_OFFICIAL
 DEFINES += -DMOZILLA_OFFICIAL
 endif
 
-APP_UA_NAME = $(shell echo $(MOZ_APP_DISPLAYNAME) | sed -e's/[^A-Za-z]//g')
-DEFINES += -DAPP_VERSION="$(MOZ_APP_VERSION)" -DAPP_UA_NAME="$(APP_UA_NAME)"
+DEFINES += -DAPP_VERSION="$(MOZ_APP_VERSION)"
 
 ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
 LIBS	+= -framework CoreAudio -framework AudioToolbox -framework AudioUnit -framework Carbon
 endif
 
 ifeq ($(OS_ARCH),WINNT)
 #
 # Control the default heap size.

--- a/mail/app/profile/all-thunderbird.js
+++ b/mail/app/profile/all-thunderbird.js
@@ -39,18 +39,16 @@
 #filter substitution
 
 #ifdef XP_UNIX
 #ifndef XP_MACOSX
 #define UNIX_BUT_NOT_MAC
 #endif
 #endif
 
-pref("general.useragent.extra.thunderbird", "@APP_UA_NAME@/@APP_VERSION@");
-
 pref("general.useragent.locale", "@AB_CD@");
 pref("general.skins.selectedSkin", "classic/1.0");
 
 #ifdef XP_MACOSX
 pref("browser.chromeURL", "chrome://messenger/content/messengercompose/messengercompose.xul");
 pref("mail.biff.animate_dock_icon", false);
 #endif