Review how to troubleshoot startup settings, including the boot process and boot issues and BCD repair.
- [Instructor] We've seen that you can access the startup settings that are available from the advanced options menu of the Windows startup recovery environment. You can use these settings to modify the Windows 10 startup behavior and also troubleshoot and recover Windows in the event of boot errors or other stability issues. Let's see how the boot process works. The main steps involved include when the PC is turned on the system clock triggers the CPU to initiate. The CPU then checks the BIOS ROM to look for startup information.
Checks are then done to make sure that the PC components such as the hard drive, keyboard, sound card, port, memory, and battery are all working correctly. The BIOS then looks for the operating system and selects the boot sequence to decide how to boot and from where the operating system will be started from. The operating system will initialize and then take over the boot process. The boot manager will manage the start process, finding configuration information in the boot configuration data, or BCD store, and then Windows performs another check of the system memory and then loads the device drivers for any attached peripherals and starts any programs included in the startup menu.
Once all of this has been done the PC is fully booted and ready to use. A common reason for Windows to fail to boot is that it cannot find the operating system. In most cases Windows 10 will be on the PC, but for some reason Windows cannot find it. The BCD, or boot configuration data, contains the information used by the boot manager during the boot process to locate Windows. If any BCD information is missing or corrupted then it will need to be repaired or replaced.
BCD issues can be caused by viruses, power outages, or updates. We have two options for solving boot configuration data issues. These ae either rebuild the BCD or manually repair the boot system. In the event of an issue that BCD can be rebuilt by using the advanced startup menu command prompt option. You can use the command-line tool Bootrec to scan the BCD and check for missing installation files.
Additionally you can use the BCDEdit command-line tool for managing your BCD. You can rebuild the BCD using the Bootrec tool. If entries are found to be missing inside the BCD then Windows 10 will ask you if you want to add the missing information to the BCD file. Alternatively, you could rename the current BCD file, so effectively ignoring it, and then rebuild the BCD file from scratch. There are several command-line options for the Bootrec Tool.
These are /FixMbr which resolves master boot record corruption issues, /FixBoot which writes a new boot sector to the system partition and is useful if the boot sector is damaged or if you have an earlier version of the Windows operating system that was installed after Windows 10, /ScanOs which scans all disks for installations of modern versions of Windows. You can use it to list the Windows installations that the boot manager window does not list.
And finally, /RebuildBcd. This scans the PC for installations of modern versions of Windows and allows you to select the installations that you want to add to the BCD store. You'll use this option when you need to completely rebuild the BCD store. However, sometimes the scan cannot find evidence of the missing installation files even though the files are actually missing. If rebuilding the BCD does not work you'll need to manually repair the boot system instead.
To manually repair the boot system you will need to follow these steps. First, you'll need to use the Disk Management console tool and create a new boot partition to be used as a new boot sector. And once this has been done you'll need to copy the boot files to this new partition, and then you'll use the BCDEdit command-line tool to do this. Your PC should now boot to this new boot partition. Be aware that if you've created a recovery disk or image backup then you'll need to recreate these again since manually repairing the BCD can cause issues with some recovery tools.
- Troubleshooting startup issues
- Using Windows 10 Safe Mode
- Creating a new BitLocker password
- Resolving a slow-running computer
- Managing device driver issues
- Fixing an incompatible application using a shim
- Troubleshooting computers remotely
- Troubleshooting network and remote connectivity
- Troubleshooting a VPN connection
- Migrating to a mobile device management solution
- Resolving sign-in issues