Share permissions control access to files and folders when accessed over a network share. They act as a gatekeeper, regulating entry to the shared resource itself, with options like Full Control, Change, and Read. NTFS permissions, in contrast, apply to files and folders stored locally on a drive formatted with the NTFS file system. They govern access both locally and over the network, offering much finer-grained control (over 14 basic permissions including modify, read & execute, write) applied directly to users, groups, or objects. While Share permissions apply only at the network entry point, NTFS permissions protect the resource at the file system level and travel with the data.

Practically, Share permissions might be set on a folder named CompanyData shared from a server, allowing only the Finance group Change access over the network. Meanwhile, NTFS permissions on that same CompanyData folder might grant the FinanceManagers group Modify access and the regular Finance group only Read & Execute, specifying detailed local access rights. NTFS permissions are essential for security on the local drive and for complex permission structures within shared folders across organizations and file servers.

A significant limitation of Share permissions is their lack of granularity; if the least restrictive Share permission is Full Control, but the NTFS permission only grants Read, the effective permission remains Read. Conversely, NTFS permissions offer detailed control and inheritance but are only effective on NTFS volumes. Combining both often involves setting Share permissions broadly (e.g., Full Control for Everyone) and then using the more granular NTFS permissions for real access control. Incorrect configurations, especially overlapping permissions, can create complex troubleshooting scenarios and unintended access.