I have an XP SP3 machine running a service (written by me) that runs as `NT AUTHORITY\NETWORK SERVICE` in order to access a network share. With filemon.exe I can see this service attempting to `OPEN` the network share but getting `ACCESS DENIED`.

The network share is a folder on a Windows Server 2003 SP1 machine, and this folder has share permission = `Everyone` (read) and NTFS permission = `Domain Computers` (read + execute + list folder contents). It has no other permissions explicitly granted, but inherits default permissions from `C:\`. I have verified that the XP machine is a member of `Domain Computers`.

On the machine sharing the folder I can see Successful Network Logon events from the XP machine.

On the XP machine I see only ACCESS DENIED when my service tries OPEN specific files on that folder.

It feels like I'm missing some vital step but I appear to have run out of SysAdmin clues.