diff --git a/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-01-17.sql b/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-01-17.sql
index 60627ac7c82e7..4b01b308bd318 100644
--- a/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-01-17.sql
+++ b/administrator/components/com_admin/sql/updates/mysql/3.7.0-2017-01-17.sql
@@ -1,2 +1,64 @@
 -- Sync menutype for admin menu and set client_id correct
-UPDATE `#__menu` SET `menutype` = 'main', `client_id` = 1  WHERE `menutype` = 'main' OR `menutype` = 'menu';
+
+-- Note: This file had to be modified with Joomla 3.7.3 because the
+-- original version made site menus disappear if there were menu types
+-- "main" or "menu" defined for the site.
+
+-- Step 1: If there is any user-defined menu and menu type "main" for the site
+-- (client_id = 0), then change the menu type for the menu, any module and the
+-- menu type to something hopefully not being used yet.
+UPDATE `#__menu`
+   SET `menutype` = 'main_is_reserved'
+ WHERE `client_id` = 0
+   AND `menutype` = 'main'
+   AND (SELECT COUNT(`id`) FROM `#__menu_types` WHERE `client_id` = 0 AND `menutype` = 'main') > 0;
+
+UPDATE `#__modules`
+   SET `params` = REPLACE(`params`,'"menutype":"main"','"menutype":"main_is_reserved"')
+ WHERE `client_id` = 0
+   AND (SELECT COUNT(`id`) FROM `#__menu_types` WHERE `client_id` = 0 AND `menutype` = 'main') > 0;
+
+UPDATE `#__menu_types`
+   SET `menutype` = 'main_is_reserved'
+ WHERE `client_id` = 0 
+   AND `menutype` = 'main';
+
+-- Step 2: What remains now are the main menu items, possibly with wrong
+-- client_id if there was nothing hit by step 1 because there was no record in
+-- the menu types table with client_id = 0.
+UPDATE `#__menu`
+   SET `client_id` = 1
+ WHERE `menutype` = 'main';
+
+-- Step 3: If we have menu items for the admin using menutype = "menu" and
+-- having correct client_id = 1, we can be sure they belong to the admin menu
+-- and so rename the menutype.
+UPDATE `#__menu`
+   SET `menutype` = 'main'
+ WHERE `client_id` = 1 
+   AND `menutype` = 'menu';
+
+-- Step 4: If there is no user-defined menu type "menu" for the site, we can
+-- assume that any menu items for that menu type belong to the admin.
+-- Fix the client_id for those as it was done with the original version of this
+-- schema update script here.
+UPDATE `#__menu`
+   SET `menutype` = 'main',
+       `client_id` = 1
+ WHERE `menutype` = 'menu'
+   AND (SELECT COUNT(`id`) FROM `#__menu_types` WHERE `client_id` = 0 AND `menutype` = 'menu') = 0;
+
+-- Step 5: For the standard admin menu items of menutype "main" there is no record
+-- in the menutype table on a clean Joomla installation. If there is one, it is a
+-- mistake and it should be deleted, but here we rename it so the admin can see
+-- it and delete it then. This is also to be done with menu type "menu" for the
+-- admin which we renamed before in step 3.
+UPDATE `#__menu_types`
+   SET `menutype` = 'main_to_be_deleted'
+ WHERE `client_id` = 1
+   AND `menutype` = 'main';
+
+UPDATE `#__menu_types`
+   SET `menutype` = 'menu_to_be_deleted'
+ WHERE `client_id` = 1
+   AND `menutype` = 'menu';
diff --git a/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-01-17.sql b/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-01-17.sql
index 4f13b235764f7..837a20f941ac5 100644
--- a/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-01-17.sql
+++ b/administrator/components/com_admin/sql/updates/postgresql/3.7.0-2017-01-17.sql
@@ -1,3 +1,64 @@
 -- Sync menutype for admin menu and set client_id correct
-UPDATE "#__menu" SET "client_id" = 1 WHERE "menutype" = 'main' OR "menutype" = 'menu';
-UPDATE "#__menu" SET "menutype" = 'main' WHERE "menutype" = 'main' OR "menutype" = 'menu';
+
+-- Note: This file had to be modified with Joomla 3.7.3 because the
+-- original version made site menus disappear if there were menu types
+-- "main" or "menu" defined for the site.
+
+-- Step 1: If there is any user-defined menu and menu type "main" for the site
+-- (client_id = 0), then change the menu type for the menu, any module and the
+-- menu type to something hopefully not being used yet.
+UPDATE "#__menu"
+   SET "menutype" = 'main_is_reserved'
+ WHERE "client_id" = 0
+   AND "menutype" = 'main'
+   AND (SELECT COUNT("id") FROM "#__menu_types" WHERE "client_id" = 0 AND "menutype" = 'main') > 0;
+
+UPDATE "#__modules"
+   SET "params" = REPLACE("params",'"menutype":"main"','"menutype":"main_is_reserved"')
+ WHERE "client_id" = 0
+   AND (SELECT COUNT("id") FROM "#__menu_types" WHERE "client_id" = 0 AND "menutype" = 'main') > 0;
+
+UPDATE "#__menu_types"
+   SET "menutype" = 'main_is_reserved'
+ WHERE "client_id" = 0 
+   AND "menutype" = 'main';
+
+-- Step 2: What remains now are the main menu items, possibly with wrong
+-- client_id if there was nothing hit by step 1 because there was no record in
+-- the menu types table with client_id = 0.
+UPDATE "#__menu"
+   SET "client_id" = 1
+ WHERE "menutype" = 'main';
+
+-- Step 3: If we have menu items for the admin using menutype = "menu" and
+-- having correct client_id = 1, we can be sure they belong to the admin menu
+-- and so rename the menutype.
+UPDATE "#__menu"
+   SET "menutype" = 'main'
+ WHERE "client_id" = 1 
+   AND "menutype" = 'menu';
+
+-- Step 4: If there is no user-defined menu type "menu" for the site, we can
+-- assume that any menu items for that menu type belong to the admin.
+-- Fix the client_id for those as it was done with the original version of this
+-- schema update script here.
+UPDATE "#__menu"
+   SET "menutype" = 'main',
+       "client_id" = 1
+ WHERE "menutype" = 'menu'
+   AND (SELECT COUNT("id") FROM "#__menu_types" WHERE "client_id" = 0 AND "menutype" = 'menu') > 0;
+
+-- Step 5: For the standard admin menu items of menutype "main" there is no record
+-- in the menutype table on a clean Joomla installation. If there is one, it is a
+-- mistake and it should be deleted, but here we rename it so the admin can see
+-- it and delete it then. This is also to be done with menu type "menu" for the
+-- admin which we renamed before in step 3.
+UPDATE "#__menu_types"
+   SET "menutype" = 'main_to_be_deleted'
+ WHERE "client_id" = 1
+   AND "menutype" = 'main';
+
+UPDATE "#__menu_types"
+   SET "menutype" = 'menu_to_be_deleted'
+ WHERE "client_id" = 1
+   AND "menutype" = 'menu';
diff --git a/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-01-17.sql b/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-01-17.sql
index 7bf8964d9c432..a59395f05ee34 100644
--- a/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-01-17.sql
+++ b/administrator/components/com_admin/sql/updates/sqlazure/3.7.0-2017-01-17.sql
@@ -1,6 +1,68 @@
 -- Sync menutype for admin menu and set client_id correct
-UPDATE [#__menu] SET [client_id] = 1 WHERE [menutype] = 'main' OR [menutype] = 'menu';
-UPDATE [#__menu] SET [menutype] = 'main' WHERE [menutype] = 'main' OR [menutype] = 'menu';
+-- Note: This change had to be modified with Joomla 3.7.3 because the
+-- original version made site menus disappear if there were menu types
+-- "main" or "menu" defined for the site.
+
+-- Step 1: If there is any user-defined menu and menu type "main" for the site
+-- (client_id = 0), then change the menu type for the menu, any module and the
+-- menu type to something hopefully not being used yet.
+UPDATE [#__menu]
+   SET [menutype] = 'main_is_reserved'
+ WHERE [client_id] = 0
+   AND [menutype] = 'main'
+   AND (SELECT COUNT([id]) FROM [#__menu_types] WHERE [client_id] = 0 AND [menutype] = 'main') > 0;
+
+UPDATE [#__modules]
+   SET [params] = REPLACE([params],'"menutype":"main"','"menutype":"main_is_reserved"')
+ WHERE [client_id] = 0
+   AND (SELECT COUNT([id]) FROM [#__menu_types] WHERE [client_id] = 0 AND [menutype] = 'main') > 0;
+
+UPDATE [#__menu_types]
+   SET [menutype] = 'main_is_reserved'
+ WHERE [client_id] = 0 
+   AND [menutype] = 'main';
+
+-- Step 2: What remains now are the main menu items, possibly with wrong
+-- client_id if there was nothing hit by step 1 because there was no record in
+-- the menu types table with client_id = 0.
+UPDATE [#__menu]
+   SET [client_id] = 1
+ WHERE [menutype] = 'main';
+
+-- Step 3: If we have menu items for the admin using menutype = "menu" and
+-- having correct client_id = 1, we can be sure they belong to the admin menu
+-- and so rename the menutype.
+UPDATE [#__menu]
+   SET [menutype] = 'main'
+ WHERE [client_id] = 1 
+   AND [menutype] = 'menu';
+
+-- Step 4: If there is no user-defined menu type "menu" for the site, we can
+-- assume that any menu items for that menu type belong to the admin.
+-- Fix the client_id for those as it was done with the original version of this
+-- schema update script here.
+UPDATE [#__menu]
+   SET [menutype] = 'main',
+       [client_id] = 1
+ WHERE [menutype] = 'menu'
+   AND (SELECT COUNT([id]) FROM [#__menu_types] WHERE [client_id] = 0 AND [menutype] = 'menu') > 0;
+
+-- Step 5: For the standard admin menu items of menutype "main" there is no record
+-- in the menutype table on a clean Joomla installation. If there is one, it is a
+-- mistake and it should be deleted, but here we rename it so the admin can see
+-- it and delete it then. This is also to be done with menu type "menu" for the
+-- admin which we renamed before in step 3.
+UPDATE [#__menu_types]
+   SET [menutype] = 'main_to_be_deleted'
+ WHERE [client_id] = 1
+   AND [menutype] = 'main';
+
+UPDATE [#__menu_types]
+   SET [menutype] = 'menu_to_be_deleted'
+ WHERE [client_id] = 1
+   AND [menutype] = 'menu';
+
+-- End sync menutype for admin menu and set client_id correct
 
 SET IDENTITY_INSERT #__extensions  ON;