Have you been receiving update failures with the error code mkdir_failed_pclzip? Then why haven’t you reported it? ;-)

So, on October 14, I accidentally committed a change that deliberately raised this error when PclZip was used to extract downloaded ZIP files. If ZipArchive is present, it is used instead of PclZip, so this doesn’t affect most installs by default. But, there are a lot of installs that do use PclZip, and they are “stuck” on the October 14 nightly build, and are unable to update past that point.

So, a few options to fix this:

  • You can download the latest nightly build (or WordPress 3.7 RC1 will be released soon) and manually install it. (You probably just need to copy over the file wp-admin/includes/file.php.)
  • Or, you can open up wp-admin/includes/file.php, head to about line 747 and remove the comment on the if statement, as was done in changeset 25799.
  • Or, you can install the Zip PHP extension. :-)

Of course, it is absolutely critical that an install is always able to update, even in development versions. @dd32 and I take that very seriously. Sorry for the lapse.