9.15 Windows Boot Process & Startup Error Fixes

If your system will not start, or if it is having significant problems, then you can boot your system in a variety of modes that may help you get your system up and running. There are two main ways you can select an alternate boot mode:

*1) Access the Settings app and select one of the following:* -Windows 8: *Update and Recovery > Recovery > Restart Now* -Windows 10: *Update and Security > Recovery > Restart Now* *2) Run the *msconfig.exe* utility to specify which boot mode you would like to use, then reboot the system.* Only a subset of advanced boot options are available in *Msconfig.*

Use the following recommendations to troubleshoot startup errors with the advanced boot options:

*Boot into Safe Mode and then use the appropriate tool to undo any recent changes. For example, you can:* -Use Device Manager to roll back drivers or disable devices that might be causing the problem. -Use Add or Remove Programs to uninstall software that has just been added. -Restore any settings that may have changed. -Disable unneeded services or applications that load at startup. -Use System Restore to restore the system to a known good restore point. -After booting into Safe Mode, begin by undoing the most recent change to the system. For example, if the problem started after you installed a new device driver, roll back the driver and reboot. -If undoing recent changes do not fix the problem, you could disable all unnecessary devices and services. If you can boot normally, you can identify which component was causing the problem by enabling devices and services one-by-one until the system becomes unstable.

Service fails to start

*If a service fails to start, you will see a message such as:* -At least one service or driver failed during system startup. Use Event Viewer to examine the event log for details. -Use Event Viewer to view details about the service that did not start, then try starting the service manually. If necessary, re-enable or re-install the service.

System does not power on

*If the system does not power on:* -Make sure the system is plugged in and the power strip or UPS is turned on. -Check the power switch and the power type (110 or 220 volts) on the back of the power supply. -If you have just installed a new system, make sure the system case power switch is connected to the motherboard. When you turn on the computer, you should hear both the power supply fan and the CPU fan start to spin.

System powers on, but no display is visible

*If the system powers on but there is nothing on the display, check the following:* -Verify that the monitor is connected to the computer, plugged in, and turned on. -Verify that the BIOS/UEFI is configured to use the correct video adapter. Most motherboards can be configured to use either the integrated video adapter or a PCIe video adapter installed in an expansion slot. -To display startup information on the screen, the computer needs at a minimum the CPU, memory, and a video card. Other components are not necessary. Verify that these three components are properly installed. -If necessary, reduce the system to the three components listed above and try starting the system. If that does not work, swap out components to identify the failed component. Some computers will use a series of beeps to indicate specific problems when those messages cannot be shown on the screen. In this case, consult the BIOS documentation for the meaning of the audible messages.

Corrupt MBR or partition table

*MBR* is responsible for locating the system (active) partition and loading the volume boot record (VBR). A corrupt or missing master boot record or a corrupt partition table prevents the system from loading the boot record code and finding the volume boot record and loading the boot loader program. *Symptoms of a corrupt MBR or partition table include:* -The system hangs immediately after the BIOS information is shown. *Any of the following errors:* -MBR corrupt -Invalid partition table -Error loading operating system -Missing operating system To fix the problem, boot the system from the installation disc and repair the system. Select *Troubleshoot >Advanced Options > Startup Repair.* Alternatively, you can select the *Command Prompt* option and then run the *bootrec /FixMbr* command. The /FixMbr option causes the bootrec command to rewrite the master boot record without overwriting the existing partition table on the disk.

Launch Recovery Environment

*Use this option to access system recovery tools, such as:* -Reset This PC -System Restore -System Image Recovery -Startup Repair -Command Prompt -Go Back to the Previous Build

Disable Automatic Restart on System Failure

By default, Windows is configured to reboot whenever a critical system error occurs (Blue Screen of Death). -When the error occurs, you will have only a short time before the system reboots. This might not be sufficient time to read and record the error information. -If the error occurs while you are away from your computer, you will see a message that the system has restarted, but won't have seen the error. -If the error occurs during startup, the system might continually reboot. Use the *Disable automatic restart on system failure* option on the advanced boot menu to stop the automatic reboots.

Missing or corrupt file

If the boot manager cannot locate needed operating system files on the selected boot partition, you might see the following errors occur: -Windows could not start because the following file is missing or corrupt: <filename> Please re-install a copy of the above file. -A blue screen error that describes a corrupt or missing file. This problem is caused either by a corrupt disk, corrupt files, or missing files. To correct the problem, boot the system from the installation disc and repair the system. Select *Troubleshoot > Advanced Options > Startup Repair.* Alternatively, you can select the *Command Prompt* option and then use the *copy* command to replace the file referenced by the error message with a known good copy.

Corrupt or missing DLL or system file

If you see errors about corrupt or missing DLLs or system files, either during startup or after Windows starts, boot the system from the installation disc and repair the system. Select *Troubleshoot > Advanced Options >Startup Repair.* Alternatively, you can select the *Command Prompt* option and then use the *sfc* command to run the System File Checker utility. The syntax to use with *sfc* is as follows: -Use *sfc /scannow* to scan the integrity of all protected system files and repair any file that has problems. Use *sfc /verifyonly* to scan the integrity of all protected system files, but not repair them. Use *sfc /scanfile* to scan the integrity of a specific file and repair it if it has problems. Use *sfc /verifyfile* to scan the integrity of a specific file, but not repair it.

Missing NTLDR

If you're still using Windows XP and your NTLDR is missing or corrupt. If this file gets corrupt, you're going to have to fix it. *To fix the problem, do the following:* -Boot your system from your installation CD. -In the Windows XP setup menu, press *R* to repair Windows. -Log into Windows using your administrator user and password by pressing *1.* -Copy the NTLDR file located in the i386 directory on the installation disk to the root directory of the system's hard drive. -When you're done, remove the installation disk from the system and try rebooting. That should fix the problem if your original NTLDR file is missing or corrupted. If the system experiences a blue screen error during startup or after the system has started, the default behavior is to restart Windows automatically after displaying the error. With the default configuration, the system could restart, experience the same error, restart automatically, and enter a constant cycle of error and restart. To configure the system to display the blue screen error until you manually continue, access the advanced startup options menu and then select Disable automatic restart on system failure to stop the automatic reboot cycle.

Disable Driver Signature Enforcement

Selecting this option causes Windows to not require a digital signature when loading a driver.

Corrupt boot sector

The *boot sector (also called the volume boot record or volume boot code)* is responsible for loading the operating system boot loader program (BOOTMGR). At this point in the process, the MBR has loaded, located an active partition, but there is a problem in loading the VBR, the VBR does not specify a boot loader program, or the bootloader specified in the VBR is missing or corrupt. *Symptoms of a corrupt or missing boot sector include:* -System hangs following the BIOS information screen. *Any of the following errors:* -Non-system disk or disk error -Remove disks or other media -Invalid system disk -Invalid media type -Disk Boot failure -A disk read error occurred -BOOTMGR is missing -Missing GRUB/LILO *To correct the problem you can check the following:* -Check the boot order in the BIOS/UEFI to make sure the system is booting from the correct storage device. *If the device is a removable media device, the drive should be empty (so the drive is skipped when checking for a boot disk), or the drive must have media that includes a bootable partition (for the system to boot from that drive). For example, leaving a USB device plugged in is a common cause of the non-system disk error. These errors can be avoided by disabling the USB Device option in the boot sequence or to set the integrated USB controller to No Boot.* -Boot the system from the installation disc and repair the system. Select Troubleshoot > Advanced Options > Startup Repair. Alternatively, you can select the Command Prompt option and then run the *bootrec /FixBoot command.* The /FixBoot option causes the bootrec command to write a new boot sector in the system partition.

Inaccessible boot disk

The boot loader program uses the *boot configuration database (BCD)* to locate valid Windows installations to start. If the database points to a location that does not include any operating system files, you will see a message similar to the following: -Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware. To correct the problem, boot the system from the installation disc and repair the system. Select *Troubleshoot > Command Prompt* option and then run the *bootrec /RebuildBcd* command. The /RebuildBcd option causes the bootrec command to scan all storage devices for operating systems and add them to the BCD database.

Blue screen or system hang after Windows splash screen is displayed

The most common cause of the errors at this stage are bad drivers or corrupt registry settings. To correct the problem, try the following (in this order): -If the error includes any error codes or messages, check the Microsoft website for troubleshooting information. -Boot the system into Safe Mode. In Safe Mode, rollback drivers, remove drivers, or restore to a restore point. -To identify which driver is causing the problem, enable boot logging, then read the *Ntbtlog.txt* file to identify the last driver that the system tried to load. -If you cannot boot into Safe Mode, boot into the Recovery Environment and use System Restore to restore to a restore point that was created when the system was working correctly.

Device fails to start

This message indicates that a hardware device could not be started. Begin by checking Device Manager for information about the device. If necessary, update the driver or disable the device.

Enable Boot Logging

This option creates a log file named *Ntbtlog.txt* in C:\Windows during startup. This file contains an entry for each driver loaded during the boot process. If the system does not complete a regular boot, you can look at this file to see the last driver to load before the failure occurred.

Enable Low-Resolution Video

This option loads Windows using your current video driver, but configures it to use low resolution settings and a slow refresh rate. This option is useful when the wrong video configuration settings have been used, causing the screen to be unreadable. Selecting this option gives you the ability to restore the correct video settings.

Enable Debugging

This option starts Windows in an advanced troubleshooting mode. This option is typically used by programmers, not system administrators.

Disable Early Launch Anti-Malware Protection

This prevents the early launch antimalware driver from loading when the system is booted. This could increase the system's exposure to rootkit malware packages.

Enable Safe Mode

When a computer boots in Safe Mode, only essential drivers and services are loaded (e.g., generic mouse, monitor, base storage device, keyboard, video drivers, and the Event Log service). This allows you to troubleshoot misbehaving applications, services, and drivers. *Enable Safe Mode with Networking* -Safe Mode with Networking is a variation of Safe Mode that also loads a network driver and protocol so the system can communicate on the network. This option is useful in situations where an updated driver needs to be downloaded from the Internet and installed on the system to correct a problem. *Enable Safe Mode with Command Prompt* -Safe Mode with Command Prompt starts the computer in Safe Mode and displays a command prompt.