WordPress warning: class __php_incomplete_class has no unserializer error
If you are running WordPress on GoDaddy’s WordPress shared hosting then you may have noticed this error starting to occur on page load infrequently. It appears to have started happening after the latest WordPress update.
The error seems to lie within the GoDaddy’s page caching system. Getting them to clear it on their end does temporarily solve the issue, but it does start to happen again. You can temporarily disable this caching by connecting to your site in FTP / SFTP or SSH and accessing the root of your website. From there, if you open the wp-content folder and rename object-cache.php to something like object-cache-DISABLED.php and this will stop the error from occurring.
Now this may seem a bit drastic to go in and start just disabling files, but this issue can stop any page of your website being served up to visitors. Potentially even worse it can cause errors in your Yoast sitemaps which affects site indexing with search engines like Google.
Removing the GoDaddy caching will obviously affect the site speed, so in the meantime you can use a plugin like Autoptimize to keep your site running smoothly in the meantime.
This obviously isn’t a permanent solution and hopefully GoDaddy will resolve it in this version of WordPress, if not the next. Then the cache can be enabled again by simply changing back the filename.