If you are trying to upload a theme or plugin to WordPress, specifically WordPress version 6.4.3, you may encounter an error that says “Incompatible Archive”. Although the error message is not very descriptive, it simply means that there was an issue with verifying the compressed .zip file you are trying to upload, and therefore, the upload could not be completed. This error usually occurs when the zip file is compressed on a Mac OS using Apple’s inbuilt compress folder function.

Note: This issue only affects WordPress 6.4.3 specifically. It was fixed in WordPress 6.4.4 and later, so if you’re able to, updating WordPress is the most reliable fix.

How to fix the ‘Incompatible Archive’ Error

Begin with installing and activating a code snippet plugin like WPCode on your site and add the below filter:

add_filter( 'unzip_file_use_ziparchive', '__return_false' );

Alternatively, if you don’t want to add a code filter, you can avoid the issue by re-zipping the file using a different tool instead of macOS Finder’s built-in “Compress” option, third-party tools like the Terminal zip command or apps such as Keka produce archives that don’t trigger this validation issue.

Treat this as a temporary workaround only. Once you update WordPress to 6.4.4 or later, remove this filter, it’s no longer needed and isn’t meant to be left in place permanently.

This issue was a bug in WordPress 6.4.3, specifically this changeset: https://core.trac.wordpress.org/changeset/57388.

A bug fix and core trac ticket are available to address this issue here: https://core.trac.wordpress.org/ticket/60398.

If you’re working with a Duplicator backup archive rather than a plugin/theme upload, see How to Manually Extract a Zip Backup File instead.