Download failed. Failed to write request to temporary file.

When trying to update stock Twenty Fourteen theme today, I ran into a theme update failing problem. The error message is “Download failed. Failed to write request to temporary file.”. The first reaction was file / folder permission setting. But it wasn’t the case this time.

update-theme-failed

Typical permission error message should be something like “unable to create directory” etc, the update failing could be “temporary directory” related. So I made following change in WP-CONFIG.PHP.

// Setup a temporary folder for uploading and updating
define('WP_TEMP_DIR', ABSPATH . 'wp-content/');

This fixed the problem in a heartbeat.

I still don’t quite understand why this happened, because this is a site that has been running stable for over a year. No similar error in either updating theme or plugin. You should also notice that, WP_TEMP_DIR is absent in a default WP-CONFIG.PHP.

This tip also works, in case you met error message like this: “Destination directory for file streaming does not exist or is not writable”

 

[Update: Sep 08, 2014]

This should be a server configuration issue. The web server is not configured properly to a temporary folder like “/tmp”. Using web-accessible directory like the one mentioned above can be a security risk.

Remove the line from WP-CONFIG.PHP after fixing the problem, and ask hosting company for a proper fix.