Thanks for taking the time to look!
Basically i have not changed anything in my magento for a few months i come to add a new product yesterday and got this error.
SQLSTATE: Integrity constraint violation: 1062 Duplicate entry '1321-1' for key 'UNQ_mg_CATALOGINVENTORY_STOCK_ITEM_PRODUCT_ID_STOCK_ID', query was: INSERT INTO `mg_cataloginventory_stock_item` (`product_id`, `stock_id`, `qty`, `use_config_min_qty`, `is_qty_decimal`, `use_config_backorders`, `use_config_min_sale_qty`, `use_config_max_sale_qty`, `is_in_stock`, `low_stock_date`, `use_config_notify_stock_qty`, `use_config_manage_stock`, `stock_status_changed_auto`, `use_config_qty_increments`, `use_config_enable_qty_inc`, `is_decimal_divided`) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, '2016-10-04 14:00:37', ?, ?, ?, ?, ?, ?)
When I make a new product when I save it I am greeted with this error, I have had a look around google and cant seam to find a problem that is the same as mine.
Any help or a point in the direction of help would be most appreciated!