So, today I was helping out a colleague with some WordPress installations. When adding plugins or updating ones that were there, I encountered this well commented but not resolved error…

PCLZIP_ERR_BAD_FORMAT (-10) : Unable to find End of Central Dir Record signature

Now, there’s a bunch of folks talking about this issue, with solutions ranging from not enough disk space, to permissions issues.

This issue occurred for me on a mediatemple grid server. I was not able to upload or upgrade any WordPress plugins on new or older versions of WordPress. This occurred in WordPress installs that did not have this problem before. Further, if I was on the server via the commandline, I could scp the zip files up and unzip them. The issue was only within the WordPress GUI. So, my guess is whatever process WordPress uses to unzip plugins is what’s causing the problem.

I’m pretty sure that the issue came about when the ZIP package was globally updated on the server recently. Since the php.ini file for the account was customized in some way, and it didn’t reference the correct zip extension, unpacking zip files via the WordPress GUI failed.

When I added ‘extension = zip.so’ to the php.ini file, this resolved the issue. I don’t know that this is the perfect solution for anyone else, but just another data point for folks looking for info.

Hope this helps someone out there 🙂