Hi brascatmalarky,
I am unable to effectively troubleshoot the root cause over the forums here, though here are the default exclusions that should be added by Symantec with a default installation of Exchange 2007 on a 64 bit machine:
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Symantec\Symantec Endpoint Protection\AV\Exclusions\Exchange Server]
"HaveExceptionFiles"=dword:00000001
"HaveExceptionDirs"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Symantec\Symantec Endpoint Protection\AV\Exclusions\Exchange Server\FileExceptions]
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\First Storage Group\\Mailbox Database.edb"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\Second Storage Group\\Public Folder Database.edb"=dword:00000000
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Symantec\Symantec Endpoint Protection\AV\Exclusions\Exchange Server\NoScanDir]
"C:\\Program Files\\Microsoft\\Exchange Server\\Bin"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\ClientAccess"=dword:00000001
"C:\\Program Files\\Microsoft\\Exchange Server\\ExchangeOAB"=dword:00000001
"C:\\Program Files\\Microsoft\\Exchange Server\\Logging\\Managed Folder Assistant"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\First Storage Group"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\Mailroot\\vsi 1\\BadMail"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\Mailroot\\vsi 1\\PickUp"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\Mailroot\\vsi 1\\Queue"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\MDBTemp"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Mailbox\\Second Storage Group"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Data\\IpFilter"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Data\\Queue"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Data\\SenderReputation"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs"=dword:00000001
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\Connectivity"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\MessageTracking"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\PipelineTracing"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\ProtocolLog\\SmtpReceive"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\ProtocolLog\\SmtpSend"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Logs\\Routing"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Pickup"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\TransportRoles\\Replay"=dword:00000000
"C:\\Program Files\\Microsoft\\Exchange Server\\Working\\OleConverter"=dword:00000000
"C:\\WINDOWS\\IIS Temporary Compressed Files"=dword:00000000
"C:\\WINDOWS\\system32\\inetsrv"=dword:00000000
To add these to the machine with Exchange installed:
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2008082610254148?Open&seg=ent