How are UNC Paths used when referencing data on a shared network?

Answer

What is a UNC Path?

A UNC path is a fully qualified network path that identifies a shared resource using the following format:

\\<server-name>\<shared-folder>\

Examples:

\\GISSERVER\SharedData\Transportation.gdb
\\FILESERVER\GISProjects\Utilities\WaterMain.shp
\\DataServer\EnterpriseData\ProjectA

The components of a UNC path include:

• Server/Host Name – The computer, file server, or storage device hosting the data.
• Shared Folder Name – The network share that has been made accessible to other users.
• Optional Subfolders and Files – Additional folders, geodatabases, or datasets beneath the shared location.

UNC Paths vs. Mapped Drives

These two paths may point to the same location:

G:\GISData\Transportation.gdb
\\GISSERVER\GISData\Transportation.gdb

However, mapped drives depend on a local drive-letter assignment and may not exist or may point to a different location on another machine. A UNC path references the resource directly and is therefore more portable and reliable when sharing ArcGIS Pro projects with other users.

Benefits of Using UNC Paths in ArcGIS Pro

• Provides a consistent data reference for all users accessing shared data.
• Reduces the likelihood of broken data connections when projects are shared between machines.
• Eliminates dependencies on individual drive-letter mappings.
• Supports collaborative GIS workflows where multiple users access the same network data.
• Simplifies project sharing, troubleshooting, and documentation by using a single standardized path format.
• Helps maintain consistent data access when projects are moved between workstations or opened by different users.

Important Considerations

• UNC paths always begin with a double backslash (\\).
• UNC paths do not contain drive letters such as C:, D:, or G:.
• Users must have appropriate permissions to access the shared folder.
• The hosting server or computer must be reachable on the network.
• UNC paths can be used throughout ArcGIS Pro anywhere a path to data is requested, including folder connections, geodatabases, tool parameters, and project data references.

Potential Performance Considerations

Because UNC paths access data across a network rather than directly from a local disk, performance may be slower depending on network speed, data size, and storage infrastructure. This can sometimes affect data access or map drawing performance when compared to locally stored datasets. Organizations should balance the benefits of centralized shared data management with any potential network performance considerations.

There is always some risk when storing ArcGIS Pro projects and data on a shared network location. ArcGIS Pro continuously reads from and writes to project files and datasets while managing indexes and file locks. If a network interruption, connectivity issue, or other disruption occurs during one of these operations, it can increase the risk of file corruption or data integrity issues. While storing and editing data locally is generally the recommended approach for optimal reliability and performance, some organizations rely on shared network storage due to their operational requirements.

Recommendation

When working with data stored on a shared network location, configure ArcGIS Pro projects, folder connections, and data sources to use UNC paths instead of mapped drive letters whenever possible. This helps ensure that projects remain portable, data connections remain valid across different machines, and all users reference the same authoritative data location. 

Keep in mind that datasets stored on a shared network location are typically accessed directly by all users with the necessary permissions. Any edits made to the data are applied to the shared dataset itself and are immediately reflected for other users. If a user needs to make changes independently without affecting the authoritative dataset, they should create and work from a separate copy of the data.