Occasionally, a Windows Server 2008 system can suffer
a service or application startup problem that could leave a server
incapable of completing a normal bootup sequence. Because the operating
system cannot be accessed in this case, the system remains unavailable
until this problem can be resolved.
Windows Server 2008 includes a
few alternative bootup options to help administrators restore a server
to a working state. Several advanced bootup options can be accessed by
pressing the F8 key when the boot loader screen is displayed. If the
Recovery Console was previously installed, it is listed as an option in
the boot loader screen. The advanced boot options include the following:
Safe Mode—
Starts the operating system with only the most basic services and
hardware drivers, and disables networking. This enables administrators
to access the operating system in a less functional state to make
configuration changes to service startup options, some application
configurations, and the system Registry.
Safe Mode with Networking—
The same as Safe Mode, but networking drivers are enabled during
operation. This mode also starts many more operating system services
upon startup.
Safe Mode with Command Prompt— Similar to the Safe Mode option; however, the Windows Explorer shell is not started by default.
Enable Boot Logging— Boots the system normally, but all the services and drivers loaded at startup are recorded in a file named ntbtlog.txt, located in the %systemroot% directory. The default location for this file is C:\Windows\ntbtlog.txt.
To simplify reading this file, the administrator must delete the
existing file before a bootup sequence is logged so that only the
information from the last bootup is logged.
Enable low-resolution video—
Loads the current display driver, but it displays the desktop at the
lowest resolution. This mode is handy if a server is plugged into a
different monitor that cannot support the current resolution.
Last Known Good Configuration— Starts the operating system using Registry and driver information saved during the last successful logon.
Directory Services Restore Mode— Only for domain controllers and enables for maintenance and restoration of the Active Directory database or the SYSVOL folder.
Debugging Mode—
Sends operating system debugging information to other servers through a
serial connection. This requires a server on the receiving end with a
logging server that is prepared to accept this data. Most likely,
standard administrators will never use this mode.
Start Windows Normally— As the name states, this mode loads the operating system as it would normally run.
Reboot— Reboots the server.
Return to OS Choices Menu— Returns the screen to the boot loader page so that the correct operating system can be chosen and started.
The Recovery Console
The Recovery Console
provides an option for administrators to boot up a system using
alternate configuration files to perform troubleshooting tasks. Using
the Recovery Console, the bootup sequence can be changed, alternate boot
options can be specified, volumes can be created or extended, and
service startup options can be changed. The Recovery Console has only a
limited number of commands that can be used, making it a simple console
to learn. If Normal or Safe Mode bootup options are not working, the
administrator can use the Recovery Console to make system changes or
read the information stored in the boot logging file using the type command. The boot logging file is located at C:\Windows\ntbtlog.txt
by default and exists only if someone tried to start the operating
system using any of the Safe Mode options or the boot logging option.
