After extensive testing I have identified a problem with DFS (Distributed File Share) and Nod32 in the following situation: Fileserver: Windows 2008 Server Standard edition File share: Domain based DFS-share (Windows 2000 mode) Domain AD version: Windows 2003 Native Client: Windows XP SP3 (all Windows updates) (No problem with Windows Vista) NOD: Nod32 3.0.672.0 (same result with 2.7 version) If you activate Offline files on the file share you get an unwanted behavior. When you are connected to the network and access the file share with explorer the computer reports that the server is offline. You can then connect to the fileshare again and synchronize (usually). Accessing the folder again makes it go offline everytime. I have indications that there are problems even without 'Offline Files' activated. When you attach a file from a DFS share to an email in Outlook it sometimes hangs or crashes. If you turn off real-time scanning on network shares in Nod32 there are no problems. Suggestions anyone?