Full disclosure: WP Super Cache is a great caching plugin. We’re taking the time to write this post to help some users fix the most common issues encountered when you use WP Super Cache to speed up your website. WP Rocket is a great plugin but sometimes, all you need is a little help to debug your free option instead of going for premium. This post aims to help you figure out how to fix some problems and let you know which ones require some heavy-duty technical knowledge.

How to avoid caching plugin issues

Choose your caching solution wisely. There are many free and premium WordPress caching plugins out there. Here are the main things you should consider when picking a caching plugin for your website:

  • Price: free isn’t necessarily free for you if you spend hours setting things up and getting errors. Consider how much time, effort and money you are willing to put in your caching efforts.
  • Ease of use: setting up some plugins can feel like rocket science. This doesn’t have to be the case though. Do your homework and check which solutions are best for beginners or pros.
  • Support: make sure you can rely on great documentation and human support for your plugin. Some plugins have a great community of users to help you out and others offer premium support to make sure that any issue gets resolved fast. Getting errors in WordPress is frustrating so it’s good to know you can have someone to count on.

Is WP Super Cache Bad For SEO?

We noticed some of you were wondering about that. Here’s the main point: caching is awesome to speed up a website. WordPress is one of those CMS that offers plenty of choice in terms of caching plugins. But some of these plugins can affect your website negatively if they are not configured properly.

Caching plugins need to auto renew the cache otherwise, many changes made to your website won’t be reflected. Changes made to links, text, pictures or design won’t be visible until the cache is cleared out otherwise. It can become quickly infuriating because you don’t want to find out that Google indexed some old content you thought was gone from your website. If you are a WP Super Cache user, you should remember to push the delete cache button in the settings to get WordPress to display your changes.

Another alternative is to use a plugin that’s been designed with search engine optimization in mind. WP Rocket automatically…

Will a caching plugin help CPU usage spikes?

Using a CMS like WordPress means that it must connect to the database to see if the requested page exists. If you own a high traffic website or if you see a surge in traffic due to bots or a viral post, this can quickly use up a lot of CPU resources from your server.

One way to reduce CPU usage spikes is to install and setup a caching plugin like WP Super Cache, W3 Total Cache or WP Rocket. These plugins cache the first visitor’s request of a new page to a plain HTML file on the server so that if can be served to the next visitor requesting it (unless you’ve made some changes to it in the meantime).

WP Super Cache For Developers

Developers love WP Super Cache as a caching plugin for WordPress over W3 Total Cache because it’s easier to setup and has less compatibility problems with other WordPress plugins. Still, it comes with its own set of problems so if you are a developer looking for a plugin that`s going to remain compatible and effective in the future, we recommend you check out our WP Rocket developer license (unlimited websites). Let other developers work on keeping your websites’ caching secure, up-to-date and efficient for years to come.

Fixes for common WP Super Cache error notifications

WP Super Cache may break WordPress plugins, themes or your ability to even log into WordPress depending on its compatibility with other plugins or themes used and the overall configuration of this caching plugin. So how can you tell if this plugin is causing all your troubles? Typical symptoms are a spikes in CPU usage, 500 errors or pages not displaying correctly, WooCommerce shopping carts not updating or showing the wrong order. Here are some common errors that you can encounter when using WP Super Cache:

Failed To Acquire Key 0x152b: Permission Denied

File locking errors such as “failed to acquire key 0x152b: Permission denied in…” or “Page not cached by WP Super Cache. Could not get mutex lock.” mean that you may have to use file locking. File locking is a mechanism that restricts access to a file by allowing only one user or process access at any specific time. To get rid of this error you must edit wp-content/wp-cache-config.php and uncomment “$use_flock = true” or set $sem_id to a different value. Alternatively, you can choose to disable file locking by going to the Admin screen but this should be a last resort to solve this WP Super Cache issue.

500 Internal Server Error messages

Sometimes, WP Super Cache will cause 500 errors to pop up upon installation or upon updating. In those cases, the easiest fix is to uninstall the plugin and to do a fresh install of WP Super Cache.

If you’ve been getting these 500 errors pretty regularly when using WP Super Cache, maybe it’s time to think about using a new caching plugin.

WP Super Cache 0 Cached Pages

This issue requires intermediate to expert knowledge to be fixed. Oftentimes, it has something to do with the wp-settings.php file. You need to make sure that there are no missing line in that file. You can read a good tutorial to help you along. If you don’t feel confident doing this by yourself, consider asking your developer or switching to a caching plugin that’s more user-friendly.

WP Super Cache Delete Cached Pages

This isn’t an error per say but if you are looking for a way to delete cached pages you could be looking to do two very different things: clearing your cache or excluding certain pages from being cached. If you are looking to clear your cache, you can go to the plugin’s settings and click on “Delete Cache”.

How to Exclude Pages in WP Super Cache

Go to the plugin’s settings and in Advanced, select the accepted filenames and rejected URIs to add the URLs you wish to exclude. Save your new settings and you should be good to go. Normally, WC 1.4.2+ sets the DONOTCACHEPAGE, constant which means you shouldn’t have this issue with the latest version of WordPress and of WP Super Cache. If the problem persists in WooCommerce, we recommend switching to WP Rocket as it is 100% compatible with WooCommerce. It guarantees you won’t ever have these issues again.

How To Uninstall WP Super Cache WordPress Plugin

If you suspect that WP Super Cache is causing issues on your website or if you would like to install another WordPress caching plugin, it is very important to make sure that you uninstall it the right way. Otherwise, it could haunt you and your load time performance!

Sidenote if you are considering WP Rocket: the plugin will automatically detect other caching plugins and let you know that you should get rid of certain files via FTP. Within the wp-content/cache folder, the only 2 folders WP Rocket creates are /min and /wp-rocket. All others should be removed.

Tutorial Requirements

You should have:

  • A WordPress website setup
  • Be using WP Super Cache Plugin
  • Have admin access to the WordPress website
  • Have FTP access to the web server

Estimated Completion Time: < 15 Minutes

Difficulty: Medium

Step 1: Turn Off All Caching

Go to the WP Super Cache settings page WordPress and clear the cache.

Step 2: Deactivate and Delete the Plugin

Go to the plugins page and deactivate WP Super Cache. Once that’s done, you should see the Delete option appear. Go ahead and delete the plugin.

Step 3: Remove Files From the Web Server

Back everything up before you remove files, just in case. Remove the WP_CACHE define from wp-config.php. Look for define( ‘WP_CACHE’, true ); and remove the files wp-content/advanced-cache.php and wp-content/wp-cache-config.php.

If you plan on installing WP Rocket, you can also delete the entire wp-content/cache folder to make sure everything is removed. WP Rocket will recreate this folder and you’ll be set.

Step 4: Solve any .htaccess errors caused by WP Super Cache

Make sure that no WP Super Cache rules remain in your .htaccess file after you uninstall it by removing the Super Cache mod_rewrite rules from the file. Create a backup of your file before you delete anything from it. Once modified, just reupload it to the server, check that everything works and you are good to go.

That’s it, wave goodbye to WP Super Cache!

The Elevator Pitch, or Why you should switch to WP Rocket

We’ll make it short and sweet:

  • It’s always compatible with WordPress, WooCommerce and CDNs.
  • It gets s#@! done. Your WordPress will be blazingly fast after your setup.
  • Switching to WP Rocket is easy and our plugin will tell you if you have other caching things lurking in WordPress that should be removed.
  • We have awesome support! Our Rocketeers are very active helping customers solve their issues.
  • WP Rocket is easy to use. We mean it. It is seriously easy to get started.

Try it for yourself: Get WP Rocket now!

And if for some reason you aren’t convinced, we have a 14-day money back guarantee.