Whenever a Joomla article or category is created, the system records the account that created it. This is useful for content items where we also want to display a link to the user who wrote the article, or for displaying content authored by a specific Joomla user.  The warning message "JUser: :_load: Unable to load user with ID: XX" is telling us that the user with the XX id number could not be loaded, typically because that user has been deleted.

Note that this message is a warning rather than an error, so while it can be annoying and may show notices or warnings it won't break your site. In the future, when users leave your organisation it is better practice to disable their Joomla account rather than to delete it. That prevents this issue from arising again.

Troubleshooting a Joomla Update problem

A few things can go wrong when updating Joomla though later releases tend to have fewer and fewer issues. We describe some common issues and provide solutions here as well as examining tools to diagnose the root causes.

1. One-click didn't work. The one-click update basically grabs the update files from the Joomla code repository and installs them similar to the way extensions get installed. If you're behind a firewall or on a weak connection this can fail. In this case, you have the option of downloading the upgrade package ZIP file manually and installing it via the Joomla update extension. If that fails there is a third option where you extract the contents of the upgrade package and overwrite the files on your Joomla installation. If you use that method you'll also need to follow our next troubleshooting tip to apply the database update.