When users log on with the Environment Manager agent running and your configuration applied, they are not able to access network shares. Attempting to access any network shares through File Explorer, Internet Explorer or by other means fails citing "Access to the resources has been disallowed".
The cause for this is that the Environment Manager configuration has an item in it that sets this Group Policy / Administrative Template element:
Path: User Configuration\AdministrativeTemplates\Start Menu & Taskbar
Policy Name: Remove Run menu from Start Menu
This sets a registry value as below:
This policy, by design, restricts the user from accessing UNC paths as well as some local paths and drive letters. If Environment Manager is configured to set this value Windows will honour it.
As this is a group policy provided by Microsoft, please investigate using the information above and work with them to resolve this issue.