I think i've found a bug with the Wordpress Toolkit in Plesk 12.5.
When updating plugins, tick one that needs to be updated, then click on Update at the top of the screen.
Plesk will try to update the selected plugin across ALL detected Wordpress sites, instead of just the ones that need updating on. As a result it will throw a bunch of errors where it tries to update the plugin on sites that don't have it installed.
The same thing applies to updating Themes.
Plesk 12.5.30 Update #30
When updating plugins, tick one that needs to be updated, then click on Update at the top of the screen.
Plesk will try to update the selected plugin across ALL detected Wordpress sites, instead of just the ones that need updating on. As a result it will throw a bunch of errors where it tries to update the plugin on sites that don't have it installed.
The same thing applies to updating Themes.
Plesk 12.5.30 Update #30