We came across a problem getting a Joomla! 1.7.1 vanilla install to work on a Windows server at one of our clients - during the installation process it was not able to create the _menu table - everything else seemed to work OK!

On closer inspection we found that there was a bug in MySQL which caused problems with large varchar fields (and the menu table includes two such fields) which prevented this table from being created.

To get around this we had to edit the joomla.sql file to reduce down the size of these fields (see bold fields below) - we set it to 255 and this allowed the installation to proceed.  At present we're unsure if this is a bug with the version of MySQL installed on the client's server, their setup, or something to do with the Joomla! installer - but we'll let you know if we find out more (if you know more, please comment on the post below!)

CREATE TABLE `#__menu` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `menutype` varchar(24) NOT NULL COMMENT 'The type of menu this item belongs to. FK to #__menu_types.menutype',
  `title` varchar(255) NOT NULL COMMENT 'The display title of the menu item.',
  `alias` varchar(255) NOT NULL COMMENT 'The SEF alias of the menu item.',
  `note` varchar(255) NOT NULL DEFAULT '',
  `path` varchar(1024) NOT NULL COMMENT 'The computed path of the menu item based on the alias field.',
  `link` varchar(1024) NOT NULL COMMENT 'The actually link the menu item refers to.',
  `type` varchar(16) NOT NULL COMMENT 'The type of link: Component, URL, Alias, Separator',
  `published` tinyint(4) NOT NULL DEFAULT '0' COMMENT 'The published state of the menu link.',
  `parent_id` int(10) unsigned NOT NULL DEFAULT '1' COMMENT 'The parent menu item in the menu tree.',
  `level` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'The relative level in the tree.',
  `component_id` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'FK to #__extensions.id',
  `ordering` int(11) NOT NULL DEFAULT '0' COMMENT 'The relative ordering of the menu item in the tree.',
  `checked_out` int(10) unsigned NOT NULL DEFAULT '0' COMMENT 'FK to #__users.id',
  `checked_out_time` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00' COMMENT 'The time the menu item was checked out.',
  `browserNav` tinyint(4) NOT NULL DEFAULT '0' COMMENT 'The click behaviour of the link.',
  `access` integer unsigned NOT NULL DEFAULT '0' COMMENT 'The access level required to view the menu item.',
  `img` varchar(255) NOT NULL COMMENT 'The image of the menu item.',
  `template_style_id` int(10) unsigned NOT NULL DEFAULT '0',
  `params` TEXT NOT NULL COMMENT 'JSON encoded data for the menu item.',
  `lft` int(11) NOT NULL DEFAULT '0' COMMENT 'Nested set lft.',
  `rgt` int(11) NOT NULL DEFAULT '0' COMMENT 'Nested set rgt.',
  `home` tinyint(3) unsigned NOT NULL DEFAULT '0' COMMENT 'Indicates if this menu item is the home or default page.',
  `language` char(7) NOT NULL DEFAULT '',
  `client_id` tinyint(4) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`),
  UNIQUE KEY `idx_client_id_parent_id_