The file is only editable by the user root so you'll need to use a text editor that can authenticate (like BBEdit or TextWrangler) or do this in the Terminal. In order to fix the slow SMB browsing you will need to edit the smb.conf file on your Mac. This makes the Mac work just as fast as my Windows 7 workstation when connecting to Windows servers.

Out of pure frustration I started playing with settings in my SMB configuration and have found a way in Mac OS 10.6.7 to speed the process up drastically to where navigating folders is almost instantaneous (including over my VPN). To make things even worse I do most of my work through a Cisco SSL VPN loaded on my Mac from home over a broadband connection. I utilize my Mac to access the office Windows 20 file servers and the speed to access these shares makes it almost impossible to work from a Mac. By default in Mac OS X browsing to Windows 20 Servers is extremely slow, navigating from one directory level to the next can take a minute or longer.

Disable folder preview mac os x