Hi Jaime,

mod/feedback:viewarchive capability is a standard capability for the feedback activity that should always exist. It looks like something strange happened on or around your last upgrade which has removed that capability from the database, which should never normally happen. The Feedback module has not had an upgrade script since November 2013 so there was nothing in any of the 2.6 point releases that would have caused this deliberately.

While there are fairly straightforward ways to resolve this they would require a sysadmin with access to the server and database, so this one would be best dealt with by getting your Totara partner to raise a formal support ticket on the Totara helpdesk.

I'm concerned though as to what happened originally - if one record has been removed, there may be other data missing which could have unpredictable effects. Your partner should also check the system logs from the time of the upgrade to see if they can determine what caused this.

As far as 'Unsubscribe users from courses after' is concerned, that is an old 1.x setting that was removed way back in 2.0. From moodle.org:

Note: For users who have upgraded to Moodle 2 from 1.9, the setting 'Unsubscribe users from courses after' in Cleanup has been replaced by 'Unenrol inactive after' in Self enrolment. i.e. the setting now applies ONLY to users who self-enrolled.