He he! Today I had an upgrade in my crystal ball. No more static; perfectly clear images and very precise mind reading :)
No, seriously. You are the third person today with the same problem. It has to do with how jUpgrade screws up all IDs, including menu item IDs. The end result is that an otherwise free menu item ID ends up being used, therefore screwing up the update's SQL script.
What you need to do is run the following SQL command against your database, using phpMyAdmin:
INSERT INTO `#__menu` (`menutype`, `title`, `alias`, `note`, `path`, `link`, `type`, `published`, `parent_id`, `level`, `component_id`, `ordering`, `checked_out`, `checked_out_time`, `browserNav`, `access`, `img`, `template_style_id`, `params`, `lft`, `rgt`, `home`, `language`, `client_id`) VALUES
('menu', 'com_joomlaupdate', 'Joomla! Update', '', 'Joomla! Update', 'index.php?option=com_joomlaupdate', 'component', 0, 1, 1, 28, 0, 0, '0000-00-00 00:00:00', 0, 0, 'class:joomlaupdate', 0, '', 41, 42, 0, '*', 1);
replacing #__ with your site's database prefix.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!