Fix “chmod(): Operation not permitted in wp-fastest-cache” in WP Fastest Cache

If you are wondering what is broken: most of the time, it is not WP Fastest Cache. It is the permissions and ownership on your wp-content/cache folders.

Why this error shows up

This warning comes from PHP’s chmod() function. WP Fastest Cache calls it when it creates or clears cache files.

When PHP tries to change file or folder permissions and the server blocks it, you get:

PHP Warning: chmod(): Operation not permitted in /wp-content/plugins/wp-fastest-cache/...

That usually means one of these:

• The /wp-content/cache folders are not writable by PHP.
• The folders are owned by a different user than the one running PHP.
• Your host blocks chmod() or mounts part of the filesystem as read only.

Step 1 - Confirm the exact error and path

First, make sure the warning is really coming from WP Fastest Cache and not another plugin.

• In your hosting panel or via FTP, open your PHP error log or wp-content/debug.log.
• Look for a line like:chmod(): Operation not permitted in /wp-content/plugins/wp-fastest-cache/...
• Note the full path after in. It tells you which file is trying to run chmod().

If the path points to /wp-content/plugins/wp-fastest-cache/ or /wp-content/cache/, you are in the right place.

Step 2 - Fix the cache folder permissions

WP Fastest Cache stores its cache under /wp-content/cache/. Those folders must exist and be writable by the web server.

Check and adjust via File Manager or FTP

1. Connect with FTP or your host’s File Manager.
2. Go to wp-content/cache/.
3. Make sure these folders exist:
   • /wp-content/cache
   • /wp-content/cache/all
   • /wp-content/cache/wpfc-minified
   • /wp-content/cache/wpfc-mobile-cache (if you use mobile cache)
4. Set each of those folders to permission 755:
   • In most file managers, this is “Change Permissions” or “CHMOD” for the folder.
   • Directories should be 755, not 777.

Clear the cache in WP Fastest Cache → Delete Cache, then browse a few pages. Check the log again to see if the warning went away.

Fix via SSH (for developers and VPS users)

If you are comfortable with SSH and know your WordPress path:

# adjust this path to your install root
cd /var/www/html/example.com

# set directory permissions (folders only) under wp-content/cache to 755
find wp-content/cache -type d -exec chmod 755 {} \;

Reload the site and watch the logs for a few minutes.

Step 3 - Fix folder ownership

If the warning persists even after setting 755, the owner of the cache folders is probably wrong.

On many servers, PHP runs as something like www-data or apache. If the cache folders are owned by root or another user, PHP cannot change permissions and you get Operation not permitted.

Check owners

Via SSH:

cd /var/www/html/example.com
ls -ld wp-content/cache wp-content/cache/*

Look at the user and group columns. The cache folders should match the rest of your WordPress files.

Change ownership (VPS or dedicated server)

If you control the server and know the correct user (replace USERNAME with yours):

sudo chown -R USERNAME:USERNAME /var/www/html/example.com

This is essentially what WP Fastest Cache itself recommends when you have persistent permission warnings on the cache folders.

If you are on shared hosting and cannot change the owner, open a ticket with your host and send them:

• The exact chmod(): Operation not permitted line.
• A note that /wp-content/cache and its subfolders need to be writable by the web server.

Step 4 - Check for hosts that block chmod or use read only paths

Some managed hosts restrict what PHP can do:

• They may disable chmod() in disable_functions.
• They may mount part of the filesystem as read only, and expect plugins to write only in specific folders.

Quick checks

• Ask your host if chmod() is allowed for your account.
• Ask if /wp-content/cache/ is fully writable, or if you should use another path for cache.
• If you are on a platform like Pantheon, WP Engine, or similar, check their docs for using third party cache plugins with their file layout.

If your host confirms that they block chmod() or write access to /wp-content/cache/, you have two realistic options:

• Switch to the host’s built in caching instead of WP Fastest Cache.
• Ask them to adjust permissions or move the cache folder to a writable location.

Step 5 - Temporary workarounds if you just need the site stable

If you cannot fix server permissions right away, you can at least stop the warnings and avoid bigger problems.

Option 1 - Disable WP Fastest Cache

• Go to Plugins → Installed Plugins.
• Deactivate WP Fastest Cache.
• Check your logs again. The chmod() warnings should stop.

Your site may be a bit slower, but it should be stable while you or your host fix permissions.

Option 2 - Reset the cache folder

If you have proper file access and ownership but the cache is still acting up:

• Deactivate WP Fastest Cache temporarily.
• Rename wp-content/cache to something like cache_old.
• Create a new empty wp-content/cache folder with permission 755.
• Reactivate WP Fastest Cache and clear cache from its settings.

WP Fastest Cache will recreate its internal folders inside the new cache directory.

When to involve your host

You should contact hosting support if:

• You cannot change file ownership yourself.
• chmod() is disabled at the PHP level and they refuse to enable it.
• /wp-content/cache is on a read only filesystem.

When you open a ticket, include:

• The exact PHP warning line.
• A note that WP Fastest Cache needs to write to and change permissions on /wp-content/cache and its subfolders.
• A recent screenshot or copy of the folder permissions and owners.

Verification checklist

Once you or your host have made changes, confirm that:

• You can clear cache in WP Fastest Cache → Delete Cache without errors.
• /wp-content/cache and its subfolders exist and are set to 755, owned by the correct user.
• Your PHP error log stays clean of new chmod(): Operation not permitted in wp-fastest-cache entries.
• Your site still loads quickly and serves cached pages as expected.

Still stuck?

For AI help

Hit Continue Chat below and send me:

• The full chmod(): Operation not permitted line from your log.
• A screenshot or copy of the permissions and owners on /wp-content/cache.
• Your hosting provider name and whether you are on shared, VPS, or managed WordPress hosting.

I will help you narrow down whether it is a pure permission issue, an ownership mismatch, or a host level restriction.

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