The iSCSI Software Initiator Setup program does not select the default options as expected

When you try to install the Microsoft iSCSI Software Initiator, the iSCSI Software Initiator Setup program does not select the default options as expected. Instead, the iSCSI Software Initiator Setup program selects the options as follows:

• The Initiator Service check box is not selected.
• The Software Initiator check box is not selected.
• The Microsoft MPIO Multipathing Support for iSCSI check box is selected.

If you continue the installation together with the options selected as described, the Microsoft MPIO components may be updated. However, the iSCSI Initiator Service component and the iSCSI Initiator component are not actually installed.

This issue occurs when a third-party device-specific module (DSM) is installed already.

To work around this issue, manually select the options to correctly install the service that is required.

For example, to install the default options in the iSCSI Initiator Installation wizard, make sure that the following options are selected as follows:

• The Initiator Service check box is selected.
• The Software Initiator check box is selected.
• The Microsoft MPIO Multipathing Support for iSCSI check box is not selected.

When you select the Microsoft MPIO Multipathing Support for iSCSI check box, the core MPIO component files and the Microsoft iSCSI Device Specific Module are installed. This lets iSCSI Software Initiator and the host bus adapter (HBA) perform session-based multipathing to a target that supports multiple sessions to a target. If the version of the MPIO core files is later than the version that is installed on the computer, the core MPIO files are upgraded to the latest version that is part of the installation package.

MPIO is supported on Windows 2000 Server platforms, on Windows Server 2003 platforms, and on later Windows Server platforms. MPIO is not supported on Windows XP or Windows 2000 Professional. When you install the iSCSI Software Initiator package on either Windows XP or Windows 2000 Professional, the Microsoft MPIO Multipathing Support for iSCSI check box is unavailable.

The following drivers are installed when you install the MPIO component:

• Mpio.sys (multipath bus-driver)
• Mpspfltr.sys (port-driver filter)
• Mpdev.sys (replacement disk driver)
• Msiscdsm.sys (device specific module driver for iSCSI)

Note Many third-party vendors have MPIO-based solutions distributed with their storage arrays which include the core MPIO binaries and a third-party DSM.