I've had this problem for a long time, here is the basics of it... I use a mixed environment of Windows 7/8 computers with Mac OSX Lion/Mountain Lion. Whenever a Windows computer creates a file on a SMB share on the Mac it no longer has group permissions, only the person who created or updated it can access it. My solution has been to go onto the Mac system and reset permissions for the entire directory structure then everyone can see it again. About the only thing on this that I can find was for OSX pre Snow Leopard that mentioned editing the SMB.CONF file to fix their particular problem (similar to mine, http://www.gladsheim.com/blog/2009/09/19/osx-leopard-and-samba-permissions/). The problem is that now Lion and Mountion Lion no longer have an SMB.CONF file (another web search pointed to the com.apple.smbd.plist (http://kidsreturn.org/?s=smb.conf) but it's an XML file now and I'm not clear on what should be done to THAT to fix the problem. So, short of me writing an Applescript to run every hour to fix permissions, does anyone know a solution to this very frustrating problem? Thank you in advance for any advice or solutions you can offer!