This is possibly a one-off and its not at all certain whether Symantec Mail Security is even at fault, however I had an issue this morning on our Exchange 2007 server that has caused me a little grief, so I thought I should document it here and ask others to comment.

My environment:
Windows Server 2003 64-bit and Exchange 2007 with all the latest SPs and patches

Recently I had cause to install/configure NFS on this server, which does triple duty as both a mail server, file server and domain controller, so that we could store files from off our VMware servers.  It was all working swimmingly until this morning.  Sequence of events as best I can piece it together:

24 FEB ... upgraded from v6.0.9 to v6.0.10 of Symantec Mail Security for MS Exchange
26 FEB ... Windows Updates installed, including .NET Framework 3.0 SP2
01 MAR ... server was rebooted
05 MAR ... minor changes made to Default Domain Policy (reverting from customised back to default password values) resulting in many domain users needing to undergo a password change
10 MAR EARLY MORNING ... server stopped sending email

People reported mail being stuck in their Outlook Outbox.  This error was in the logs:

    The execution time of agent 'SMSMSESMTPAgent' exceeded 300000 (milliseconds) 
    while handling event 'OnEndOfData'. This is an unusual amount of time for an
    agent to process a single event. However, Transport will continue processing
    this message.

I then tried manually stopping all the Exchange services, however the Information Store process would not stop.  After waiting about 15 minutes, I eventually had to reboot the server.  After the reboot, Exchange was working fine again ... but ... it started throwing Event ID 4004 errors relating to "Server for NFS" service. 

NFS services would not start.  As we are not using NFS much now, I have uninstalled it, so not much harm done, but I am at a loss to understand what happened to the server which triggered this issue.

I couldn't find many specific matches on the error messages when I Googled, however one of the suggestions made was that the NFS problems might be related to RPC issues (e.g. RPC finding itself on the 'wrong port' which makes NFS get confused).  I am pretty sure that Symantec Mail Security for Exchange utilises RPC in some way.  But there's a 2 week gap and a lot of activity between the upgrade of Symantec Mail Security and the issues which hit this morning.

So am wondering whether there have been any updates released recently which have caused anyone else any grief with Exchange 2007 or with NFS.