diff --git a/config/autoconf.mk.in b/config/autoconf.mk.in
index b88ffcbbbac..ee16b1b9b63 100644
--- a/config/autoconf.mk.in
+++ b/config/autoconf.mk.in
@@ -177,7 +177,7 @@ JAR="@JAR@"
 
 TAR=@TAR@
 
-MAKENSIS=@MAKENSIS@
+MAKENSISU=@MAKENSISU@
 
 RM = rm -f
 
diff --git a/configure.in b/configure.in
index 6f55992f6c9..ef4b5aaf086 100644
--- a/configure.in
+++ b/configure.in
@@ -6433,26 +6433,26 @@ if test -n "$MOZ_INSTALLER" -a "$OS_ARCH" = "WINNT"; then
     # the path.
     REQ_NSIS_MAJOR_VER=2
     MIN_NSIS_MINOR_VER=33
-    MOZ_PATH_PROGS(MAKENSIS, $MAKENSIS makensisu-2.46 makensisu makensis)
-    if test -z "$MAKENSIS" || test "$MAKENSIS" = ":"; then
+    MOZ_PATH_PROGS(MAKENSISU, $MAKENSISU makensisu-2.46 makensisu makensis)
+    if test -z "$MAKENSISU" || test "$MAKENSISU" = ":"; then
         AC_MSG_ERROR([To build the installer you must have the latest MozillaBuild or Unicode NSIS with a major version of $REQ_NSIS_MAJOR_VER and a minimum minor version of $MIN_NSIS_MINOR_VER in your path. To build without the installer reconfigure using --disable-installer.])
     fi
     changequote(,)
-    MAKENSIS_VER=`"$MAKENSIS" -version 2>/dev/null | sed -e '/-Unicode/!s/.*//g' -e 's/^v\([0-9]\+\.[0-9]\+\)\-Unicode$/\1/g'`
+    MAKENSISU_VER=`"$MAKENSISU" -version 2>/dev/null | sed -e '/-Unicode/!s/.*//g' -e 's/^v\([0-9]\+\.[0-9]\+\)\-Unicode$/\1/g'`
     changequote([,])
-    if test ! "$MAKENSIS_VER" == ""; then
-        MAKENSIS_MAJOR_VER=`echo $MAKENSIS_VER | $AWK -F\. '{ print $1 }'`
-        MAKENSIS_MINOR_VER=`echo $MAKENSIS_VER | $AWK -F\. '{ print $2 }'`
+    if test ! "$MAKENSISU_VER" == ""; then
+        MAKENSISU_MAJOR_VER=`echo $MAKENSISU_VER | $AWK -F\. '{ print $1 }'`
+        MAKENSISU_MINOR_VER=`echo $MAKENSISU_VER | $AWK -F\. '{ print $2 }'`
     fi
     AC_MSG_CHECKING([for Unicode NSIS with major version == $REQ_NSIS_MAJOR_VER and minor version >= $MIN_NSIS_MINOR_VER])
-    if test "$MAKENSIS_VER" == "" ||
-       test ! "$MAKENSIS_MAJOR_VER" == "$REQ_NSIS_MAJOR_VER" ||
-       test ! "$MAKENSIS_MINOR_VER" -ge $MIN_NSIS_MINOR_VER; then
+    if test "$MAKENSISU_VER" == "" ||
+       test ! "$MAKENSISU_MAJOR_VER" == "$REQ_NSIS_MAJOR_VER" ||
+       test ! "$MAKENSISU_MINOR_VER" -ge $MIN_NSIS_MINOR_VER; then
         AC_MSG_RESULT([no])
         AC_MSG_ERROR([To build the installer you must have the latest MozillaBuild or Unicode NSIS with a major version of $REQ_NSIS_MAJOR_VER and a minimum minor version of $MIN_NSIS_MINOR_VER in your path. To build without the installer reconfigure using --disable-installer.])
     fi
     AC_MSG_RESULT([yes])
-    MAKENSIS="${CYGWIN_WRAPPER} $MAKENSIS"
+    MAKENSISU="${CYGWIN_WRAPPER} $MAKENSISU"
 
     # The Windows build for NSIS requires the iconv command line utility to
     # convert the charset of the locale files.
@@ -8717,7 +8717,7 @@ AC_SUBST(CYGWIN_WRAPPER)
 AC_SUBST(AS_PERL)
 AC_SUBST(WIN32_REDIST_DIR)
 AC_SUBST(PYTHON)
-AC_SUBST(MAKENSIS)
+AC_SUBST(MAKENSISU)
 
 AC_SUBST(WINCE)
 AC_SUBST(WINCE_SDK_DIR)
diff --git a/toolkit/mozapps/installer/windows/nsis/makensis.mk b/toolkit/mozapps/installer/windows/nsis/makensis.mk
index ced3f64f796..07acedba7fa 100644
--- a/toolkit/mozapps/installer/windows/nsis/makensis.mk
+++ b/toolkit/mozapps/installer/windows/nsis/makensis.mk
@@ -69,10 +69,10 @@ $(CONFIG_DIR)/setup.exe::
 	done
 	$(INSTALL) $(addprefix $(MOZILLA_DIR)/other-licenses/nsis/Plugins/,$(CUSTOM_NSIS_PLUGINS)) $(CONFIG_DIR)
 	$(INSTALL) $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/setup.ico $(CONFIG_DIR)
-	cd $(CONFIG_DIR) && $(MAKENSIS) installer.nsi
+	cd $(CONFIG_DIR) && $(MAKENSISU) installer.nsi
 # Support for building the uninstaller when repackaging locales
 ifeq ($(CONFIG_DIR),l10ngen)
-	cd $(CONFIG_DIR) && $(MAKENSIS) uninstaller.nsi
+	cd $(CONFIG_DIR) && $(MAKENSISU) uninstaller.nsi
 endif
 
 $(CONFIG_DIR)/7zSD.sfx:
@@ -95,6 +95,6 @@ uninstaller::
 	done
 	$(INSTALL) $(addprefix $(MOZILLA_DIR)/other-licenses/nsis/Plugins/,$(CUSTOM_NSIS_PLUGINS)) $(CONFIG_DIR)
 	$(INSTALL) $(MOZILLA_DIR)/toolkit/mozapps/installer/windows/nsis/setup.ico $(CONFIG_DIR)
-	cd $(CONFIG_DIR) && $(MAKENSIS) uninstaller.nsi
+	cd $(CONFIG_DIR) && $(MAKENSISU) uninstaller.nsi
 	$(NSINSTALL) -D $(DIST)/bin/uninstall
 	cp $(CONFIG_DIR)/helper.exe $(DIST)/bin/uninstall