The PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature error is usually displayed by WordPress as a result of one of two things below:
1. There’s a problem with the zip file or its format.
This issue happens mostly while trying to install the KeyDesign Addon plugin. That could happen for various reasons, such as failed internet connection during the downloading of the file. Or it could have occurred at the web server itself.
The solution is to download the plugin file from our server and upload it from Plugins > Add New.
2. Your server doesn’t have enough free disk space left.
If you still receive the same error then it may mean that there is not enough disk space on your web server. To make sure this is the case, try to upload other files to your site, such as an image, video or other plugin files. If so, then storage space is likely the issue and you would need to either remove some files from your web server or contact your hosting support to increase your storage capacity.