A、Turn on auditing for objects in the Local Security Policy and Select 'Process Tracking'. 

B、Turn on auditing for objects in the Local Security Policy and Select 'Object Access'. 

C、Use Windows Explorer to turn on auditing for the specific files. 

D、Have the administrator for domains log you on as an administrator and enable auditing for a  specific file. 

E、Turn on auditing for objects in the Local Security Policy and Select 'Account Management'. 

F、Allow only one account at a time to log on to your shared folder. Check the event viewer to  see who logged on.