I had a similar problem when I switched to a new version mongodwithout updating the data (from version 3.2, for example, to version 3.6).
In this case, it mongoddisplays ** IMPORTANT: UPGRADE PROBLEM: The data files need to be fully upgraded to version 3.4 before attempting an upgrade to 3.6; see http://dochub.mongodb.org/core/3.6-upgrade-fcv for more details.(it mongodwas launched by the key --verbose).
The link does contain detailed instructions for updating the data.
, 62 .