Hi Tim,
You are unable to open mapped drive if the application opened with Administrator privilege. By default, after installation Dashboard and Studio application will be opened with Admin privilege.
Please close both the dashboard(the launcher used to open big data studio and service manager) and Big Data Studio application and relaunch it without Admin privilege.
Now you can access mapped drive folders and files.
Note:
This is known issue in Windows from Windows 8.
Please refer the below link for more details,
Thanks,
Aravindraja T