Description
The project's default geodatabase is not a file geodatabase. Because the sublayer data for a network analysis layer must be in a file geodatabase, the new network analysis layer's sublayer data has been put in an alternate location.
File geodatabases don't support concurrent access by multiple users, so if the project is shared among multiple users, you may encounter file lock errors.
Solution
You can use the network analysis layer as normal, but don't allow multiple users to work with it at the same time.