Dmitry,

Your issue sounds similar to one I couple of few years ago - error reading files on a network drive.

Have a look at https://community.spiceworks.com/topic/1139165-windows-10-losing-mapped-drives?page=2

The gist of it is, If mapped drives are created as part of a windows group policy, they may periodically "disconnect" if the mappings are set to "Recreate". Change the setting to "Update" and see if the problem goes away.