DS‑Client can be configured to send email or pager notifications in the event of a critical backup failure. In addition, DS‑Client can regularly send mail with a summary of backup activities (during Admin processes).

DS-Client notifications can be SMTP or MAPI.

The delivery of notifications is provided by 3rd‑party mail clients installed on the DS‑Client computer and registered with the Windows Messaging Subsystem (MAPI). By design, MAPI and most mail clients cause their client applications to pop up dialog boxes to interact with a user. Because DS‑Client is an unattended service software, it would hang if it displays a dialog. Therefore, DS‑Client will only use compatible mail clients known to never display a user interface. Such mail clients are listed in the order of preference in the Registry value

The entry for Microsoft Outlook is added to this list during the installation process. DS‑Client will use the first MailClientsSupported entry installed on the computer, i.e. listed under:

The normal procedure for sending email in Windows is as follows. The client application places the message in the Outbox of a message store provider, the latter notifies the MAPI Spooler, the Spooler dispatches the message to the appropriate transport provider based on message recipients and, finally, the transport provider takes over message delivery.

Since Microsoft overlooked security and identity issues in designing the MAPI Spooler, it cannot properly work with client applications that are services. For instance, the Spooler may not be able to access Mail Profiles due to incorrect security context, and may not receive new message notifications from a message store provider by way of window messages (every service runs in its own virtual desktop and window messages do not propagate between desktops). Because DS‑Client runs as a service on Windows, it must not use the MAPI Spooler. This means DS‑Client notifications will forever remain in the Outbox of the message store provider unless the latter is tightly coupled to a transport provider, so that the two can work out between themselves how to send the message without the intervention of the MAPI Spooler.

At this time, only the Microsoft Exchange Server mail client is known to offer tightly coupled message store and transport.

You can specify the message store and transport to be used by DS‑Client by creating a Mail Profile (see below in “How to Create a Mail Profile for DS‑Client”) and selecting it in DS‑User Configuration (see “Configuring the notification settings”).

To use DS‑Client with non‑tightly coupled transports, such as Internet Mail, you can force DS‑Client to use the MAPI Spooler by setting the Registry value

to a nonzero DWORD value. Keep in mind that such use is not supported by Windows architecture and errors are bound to ensue. Make sure no other MAPI client applications are executed on the DS‑Client computer.