Joomla Update Error - Invalid Login
When updating Joomla you may see a pop-up error message with the title 'Error' and the message 'Invalid Login'.
If you see this message on your screen, one of the most likely causes is lack of disk space on your hosting account.
When updating, Joomla requires a certain amount of disk space to write the new files to and if the space is not available, you may receive the 'invalid login' error.