WordPress 3.6 Auto update failed – Possible solution

I’ve been having auto update issues within WordPress for a while now (not just to 3.6) but finally go annoyed enough to look into it.
This solution is obviously not going to help everyone but it helped me so might be of interest to others.

I was getting this error via the WP admin update panel:

Could not copy files

Installation Failed

I think the main problem, for me at least, is folder ownership. This is different from file/folder permissions (which can also be an issue but isn’t covered here)

Took me a while to sort out (a lot of website / blog/ forum / thread reading) but I have done it.

I’m on a VPS (virtual private server) with Plesk control panel – this means I have to sort all of this stuff out myself (no experts to call on & it’s certainly not me : (
The internet is my fickle friend. Takes a lot of reading to find answers but … I’ve finally resolved my problem.

My WP-content folder was set with a user group ‘psacln’
This was introduce unbeknownst* to me by the Plesk install and isn’t the default group that WP sets up and requires to be able to read, write & execute upon files & folders (from what I understand)

So, with regard to the command line stuff below, it seems that WP needs the default apache user which is generally www-data. However, it seems that on my Centos6 system (Linux OS) the apache user isn’t www-data but simply apache (www-data didn’t work for me)

So, the plesk control panel introduced the user named ‘psacln’ which was given group permissions to the WP-content folder (which includes the WP plugin & update folder) but needed an ‘apache’ user adding so WP could use the folders.

Via Putty I have SSH access to execute the following commands (I know this might seem complicate to new users. That’s because it is but I’ve managed to get here from zero knowledge of these things so I’m sure you can too … or get your host to do it : )
**anything between these are just my notes and need not be typed. I’m no expert but this is basically what each command line does from my limited knowledge**

Start Putty and connect with your server (or however you gain SSH access to your system)
At the prompt type:

cd /var/www/vhosts/yourdomain.com
**goes to the location of your WordPress install (if it’s in the root folder of your domain name. Your path might be different but you should be able to work out what it should be via your FTP client)**

chown -R apache:psacln httpdocs
**adds the ‘apache’ user to the group & gives it ownership permissions**

chmod -R g+w httpdocs/wp-content
**applies these permissions to the wp-content folder and everything in it allowing WP to read,write & execute plugins and updates**

Once done, WP auto updated as it should, which was a relief : )

I hope that helps someone.

*that’s a hell of a word : )