After the release of Norman Virus Control  5.90 some users of Norman Virus Control for Exchange plugin have reported a problem where MS Outlook clients have been unable to connect to the Exchange server, and/or the Exchange server information store hangs. The problem typically occurs in connection with definition file updates.

The problem has been identified and fixed in NVC for Exchange 5.9 Release 2. The latest version of NVC for Exchange can be downloaded here (user name and password required).