The OS Property system plugin has not been install

Osproperty system plugin (Required)
The OS Property system plugin has not been installed or published. Install this via the Joomla installer and remember to publish it.
I dont understand why it is saying this. It seams like it is installed and I have checked all the OS extensions to published?

Hi,
The System plugin is the file: plg_cronjobs_osproperty.zip.
You can install this plugin through Joomla Installation management tool at back-end of your site.
Thanks
Dam

Hi Dam thanks again.

Would it be smart to install all the plugins and do you know if there is anything els I need to install that might be missing?

Hi Martin,
This plugin is needed in case you want to use feature Expiration Management of OS Property. This feature is used to unpublished or removed properties after one time period. If you want to use this feature, you need to install and publish this plugin and then turn the feature "Expiration Management" at Back-end > OS Property > Configuration > Tab General
Thanks
Dam