A number of WordPress users who upgraded to WordPress 6.2 have been experiencing fatal and critical errors on their websites. Others have indicated that WordPress 6.2 is causing the allocated memory to be exhausted.
WordPress 6.2 critical error
WordPress 6.2 critical error is caused by the use of plugins and themes that are not compatible with 6.2. In our earlier post, we advised our subscribers to delay updating to WordPress 6.2 until plugin and theme developers have fixed compatibility and bug issues. If your host has enabled WordPress core auto-updates, then there is nothing you could do as WordPress was automatically updated.
Some of the reasons why we advised users to delay updating are; new libraries versions that lead to a mismatch of classes, full side editor rollout, deprecated functions like get_page_by_title() for search, Requests.php file, and class-requests.php among others (explained in detail in this article) that require developers to make changes in their plugins/theme for compatibility.
Out of allocated memory error
The reason why memory size gets exhausted after updating to WordPress 6.2 is because your theme or plugin is calling a function that creates an infinite loop. This means the code does not terminate. Think of when you fill a bottle with tap water then you leave the tap to continue running, it will overflow. A Function is designed to terminate at some point, if there is an error and it does not terminate it will keep repeating or executing until your memory is exhausted.
How to fix WordPress 6.2 critical error
There are a number of reasons that lead to WordPress 6.2 fatal and critical errors. We may not know exactly the issues affecting your website but as mentioned earlier, the main reason why you are seeing the error after an update is that some functions that were introduced in WordPress 6.2 cannot work with the plugins or theme you are using. Before you wait for the plugin developer to fix the specific issue, below are temporary general solutions.
Solution 1: Roll back WordPress Versions
This is the quickest and easiest solution to avoid your website being down. Roll back to the previous WP version that your website was using before the update. Here is a simple guide that we published on how to roll back WordPress Core version.
Solution 2: Disable plugins and themes
You might have done this as every solution that you will find online recommends this approach. If not, then disable or deactivate all plugins to find out which plugin is causing the error. If you cannot find any plugin with a problem then switch to any default WordPress theme like Twenty Twenty-Three to find out whether the problem is your theme. If you do not want users to see the changes happening in your website as you switch themes, then put your website under maintenance mode using a plugin like Under Construction.
Solution 3: Developer Update
This is the recommended solution if you have rolled back to the previous version of WordPress and are looking for a long-lasting solution. Contact your theme or plugin creator and ask them to update the affected files. It is important that you use the latest versions of WordPress as they come with security fixes and performance improvements.