Who has accessed/opened a file on the network and when?

Question

Pretty simple:

A certain folder with sensitive information was left accessible to users in a organization unit when it should have been private. I have fixed this, but now the department is asking if we can see who on the network, if anyone, has accessed the files.

Solution

Unless you had previously enable auditing, you're out of luck.

Here's a fairly good guide on enabling file and folder auditing:

http://www.techotopia.com/index.php/Auditing_Windows_Server_2008_File_and_Folder_Access