Hi,
Since enabling "Audit Object Access" generates a ton of logs, so to reduce the amount of logs and only get the "File System" ones you can disable this and enable the subcategory only
using the Auditpol tool with the following command.
AUDITPOL /SET /SUBCATEGORY:"File System" /SUCCESS:ENABLE /FAILURE:ENABLE
If we want to see all possible categories and subcategories, type the following line at the command prompt, and then press ENTER:
auditpol /list /subcategory:*
For details about Auditpol command, please refer to the following articles.
Auditpol
http://technet.microsoft.com/en-us/library/cc731451(v=ws.10).aspx
Auditpol set
http://technet.microsoft.com/en-us/library/cc755264(v=ws.10).aspx
How to use Group Policy to configure detailed security auditing settings for Windows Vista-based and Windows Server 2008-based computers in a Windows Server 2008 domain, in a Windows
Server 2003 domain, or in a Windows 2000 domain.
http://support.microsoft.com/kb/921469
In addition, we could also enable file and folder auditing with the following steps.
Enabling File and Folder Auditing
http://msmvps.com/blogs/richardwu/archive/2010/07/16/enabling-file-and-folder-auditing.aspx
Regards,
Andy