We are upgrading our XP (Client 4.91SP5) pcs to Windows 7 Professional 64-bit (Client 2 SP3) and are experiencing "access denied" errors when a user tries to open a file already in use by another user. I've tried installing Client 2 SP3 IR6 and the problem still persists. We do not have this problem with the XP systems. They get a message stating the file is already open and do you want to open it in read only mode. This problem is affecting all files whether they be Office 2010, PDFs, etc. Has anyone seen this? Is there a specific version of the Client that fixes this?