Fix for – The PCLZIP_ERR_BAD_FORMAT (-10) Error

Encountering the “PCLZIP_ERR_BAD_FORMAT (-10)” error message can be frustrating when you’re trying to install a new WordPress plugin.

This error message indicates that there is an issue with the plugin’s zip file format. But don’t worry, resolving this error is often quite simple. Here’s a breakdown of what might be causing the problem and how to fix it.

What Does the “PCLZIP_ERR_BAD_FORMAT (-10)” Error Mean?

This error occurs when WordPress tries to extract a ZIP archive that isn’t valid. However, the ZIP itself is often fine — the real issue is that WordPress couldn’t download it properly in the first place.

WordPress relies on curl to download plugin and theme update packages from the server. If curl (the php-curl extension) is not available, WordPress falls back to PHP stream wrappers for HTTP requests. This fallback can result in incomplete or corrupted downloads. When WordPress attempts to extract the corrupted archive, it throws the PCLZIP_ERR_BAD_FORMAT (-10) error, not because the extraction logic is broken, but because the downloaded file is not a valid ZIP.

Common Causes and Fixes

The PCLZIP_ERR_BAD_FORMAT (-10): Unable to find End of Central Dir Record signature error is caused by one of two things as below:

Case 1: There’s a problem with the zip file or its format.

It’s possible that the plugin zip file became corrupted when it was downloaded. Try downloading it from your account on our store and install (or update manually). If this happens with every update, please follow the next steps:

Case 2: Missing php-curl Extension

The most common cause on self-managed servers (VPS, dedicated) is a missing php-curl extension. Without it, WordPress cannot use curl for downloads and falls back to stream wrappers, producing corrupted ZIPs.

You can verify it on your website by navigating to WordPress Dashboard >> Tools >> Site Health. If it is missing on your server, you will see a warning like below:

To fix this, install Curl on your hosting server or ask your hosting provider. Once curl is active, WordPress will be able to download update packages properly and automatic updates should work as expected.

Case 3: Missing ZipArchive / php-zip Extension

If php-curl is already installed, the issue may be a missing ZipArchive extension (php-zip). When ZipArchive is not enabled, WordPress falls back to PclZip for extracting archives. PclZip can struggle to process certain archive formats and produces this exact error.

Ask your hosting provider to enable the ZipArchive / php_zip / ext-zip extension for your PHP version. Most managed hosts can do this quickly — once it’s active, WordPress will use ZipArchive for extractions and the updates should work without any issues.

Case 4: Server Disk Space Issue

If you still receive the same error while trying to install the zip manually, then it may mean that there’s not enough storage space on your host for WordPress to be able to unzip and upload the contents of the file.

To confirm this, try to upload other files to your sites, such as an image, video or other plugin. If you’re not able to upload large files, then storage space is likely the issue.

You can either remove some files (backups or themes & plugin that you’re not using) or contact your web host to increase your storage capacity.

We hope this document has equipped you with the knowledge to fix the “PCLZIP_ERR_BAD_FORMAT (-10)” error and successfully install your WordPress plugin.

If you have any further questions or require additional assistance, feel free to leave a comment below.