Get a CMS. Having a read only social network makes no sense

Thank you for reply Ismayil...We are testing a few functionalities thus we wanted to make it read only for a certain period of time.

Test new functionality on a staging server.
You can put your site into maintenance mode, but that will prevent user access

All files should be with ACCESS_PUBLIC level.

Try https://elgg.org/plugins/1939447/releases/1939448/download

Assuming the files_tools plugin on your system is compatible with 1.8, this error would likely be caused by a file that has been deleted or is not accessible by the user requesting it. What were you doing when we see the error? Are you logged in as an admin?

I guess it might be an access level issue, possibly connected with a Files entry within a (restricted?) group. There was an issue in older Elgg versions (as it seems at least up to Elgg 1.8) where it could happen that an entity itself was visible (or stuff like a river entry connected with this entity) but due to a more restricted access level of the container entity of this entity (e.g. container could be a group) accessing the entity itself failed.

I'm not 100% sure this is the case here but I suspect it is. Only solution then would be to upgrade to a newer Elgg version than 1.8 where this problem got fixed (hiding everything of an entity if the user lacks the necessary permissions to access the container entity).

Tidypics does not support subalbums. It would also not be easy to implement. Basically, you would have to rewrite the whole plugin - and that's not my plan at all.