To address the number of clubs with inactive managers and ensure the game continues to be competitive a new update will be released over the next few days which will automatically sack a manager if they do not login to the game for a period of time (currently 14 days). Managers will receive 3 warnings via email to remind them of this.
EDIT: the update was enabled on 28th July 2017. Players who do not log in before 11th August will begin receiving warning emails on the 8th August.
Discuss this update on the forum: http://manager.soccer/forum/d/9-discussion-14-day-inactivity-limit