Officially Microsoft doesn't support PST files via a network share: http://support.microsoft.com/default.aspx/kb/297019/ Samba's documentation suggests turning off oplocks on PST files: http://www.samba.org/samba/docs/man/Samba-Guide/happy.html#id2582162 An alternative to keeping the PST files on the network share would be to keep the PST files on the client drive and back it up to the network using Outlook Personal Folders Backup Tool: http://office.microsoft.com/en-us/outlook/HA010875321033.aspx Outlook Personal Folders Backup Tool requires some additional user training and user patience when dealing with multiple gigs of PST files, so it only works so well. I'm planning on replacing it with Backup Exec Desktop and Laptop Option to suck user data off user's laptops and into our backup system. We're using Windows servers for file sharing and we haven't run issues having the desktops keep their PST files on the network for the past 6 years or so. If you want to use backup software to deal with the PSTs, keep in mind that you first need to deal with the issue of the PST file being in use as long as Outlook is open. You could force log-off at night using a Group Policy (Local or in Active Directory) or a scheduled task that calls shutdown.exe with the appropriate switches, or you could go with a backup product that is able to deal with open files. As far as I know, Backula, BackupPC, Amanda, and other OSS backup solutions are not able to deal with open files on Windows systems. Most commercial backup products are able to deal with open files (add on license may be required) on Windows clients/servers via the Shadow Copy/Volume Snap Shot functionality built into the operating system. If you are looking for a commercial product for the purpose of sucking PSTs off of desktops and laptops, I'd look at EMC Retrospect first.