If you are seeing an error message on your Windows PC before it even begins to load then there are chances that the boot sector on your system partition is damaged, corrupted or has some files missing. This article focuses on fixing the UEFI boot process.
Let’s repair your Windows 10 bootloader!
What is the purpose of UEFI Bootloader
Boot sector; a small section there at the start of a hard drive which is created when we format a device. It carries some code and data which helps BIOS hand off control of the startup process to the widows. Moreover, it also hosts MBR i.e. Master Boot Record; it carries disk signature, a partition table for the disk, a small code known as the master boot code.
When a system starts, the initial power-on routine is handled by BIOS. It then loads it to the system’s RAM and hands it off to it. It then scans the partition table, determines active partition, loads a copy of the boot sector into the system’s RAM, hands it off to that code. It is this bootstrapping process that allows the initials bit of the Windows code to get started with the loading.
It can experience the same kinds of problems as any other part of the hard drive like missing files, corrupted files, and even physical damage. When this process fails, it shall happen after users see the BIOS information but before windows begin to load in real. You shall see the following error messages:
- Error loading operating system
- Missing operating system
- Reboot and select proper boot device
- Invalid partition table
- Bootmgr is missing
- FATAL: No bootable medium found! System halted.
If you are seeing any of these then it means you shall not be able to start Windows and need to use the windows recovery environment to do troubleshooting. Let’s walk you through this process.
Note: If your system begins to load windows, but then fails, then bootloader is not the problem. You need to try starting the PC in safe mode and troubleshooting from there. Start with system restore as it would be a good place to begin.
3 Methods on How you Can Fix UEFI Bootloader Issues in Windows 10
Check your Master-Boot Record
You can begin by starting your system into this. It is quite possible that the system has a special recovery partition that allows users to start it without requiring any physical disc. Now we to do this varies with what brand of PC we own, you shall see a message often during this telling which key to press or start and repair.
If your system does not have this or somehow you are not sure how to access it, then you can start it by using a DVD or USB with a windows installer on it.
If you do not have the disc, then you need to use another system to download a copy of windows. Create a DVD or USB install disc that ca be used to boot your own system. If PC is still operational, you may want to take some precautionary steps of creating a recovery drive or system repair disc that can be used in the future.
If you begin your system using this, then click until you see the “initial windows installation screen”, click the “Repair your computer” link in spite of starting. If you are starting from the recovery partition or disc then the screen may look a bit different from the usual but you shall end up at the same options that we are going to cover here.
- Windows shall load the recovery environment. On the first page, you need to click on the “Troubleshoot” option.
- Advanced options page appears, it carries options that we shall discuss so follow through.
- If you are using windows 7, then screens may look different. Users shall see mostly the same options including others discussed below.
Run Start-up Repair
In many cases, the user should allow windows to repair this automatically. It not only attempts to fix this or re-create the boot sector but also will scan for and try to fix other common problems related to it.
- You need to click on “Startup Repair”, on the advanced options page.
- The next page shall display all the OS detected on the system, even if the user has clicked only once. Click OS that you want to repair.
- Windows begin to checkup for related problems and attempts to repair.
- As the process is completed, windows will let you know either the repairs are successful or not. In any way, you are provided with the option to restart your system or go back to the advanced options page.
Repair Master Boot Record from CMD
If you like to handle things by yourself or an automatic repair has been failed and you are sure that the issue is with this you can use this for a quick fix.
- Click “Command Prompt” on the advanced options page.
- Once there, you shall be using bootrec In here there are some options that are useful for fixing such errors.
- To restore it, you need to type in the following command and press “Enter”.
- This issued to write a new one compatible with windows to it without over-writing the present partition table. This is quite a good start to repair such an error resulting from corruption.
- To write a new boot sector to the system partition in spite, type in the following command and press “Enter”. This shall overwrite the current one and can thus at times cause problems if you are set up to boot to a different OS.
- This won’t overwrite any data on actual partitions but you might need to reconfigure your multi-boot options after using this. The command is quite useful when the user suspects this might have been overwritten by any other OS installation or malware, or if you see this being damaged itself.
This one also offers other advanced options. Type in bootrec /? If you want to see more options for and get help with the command.
What you need to do after an OS recovery process
Once you have repaired your system successfully and are able to start windows then we recommend you to go ahead and perform a few important steps.
- In the first step, you need to run the “Disk Utility”. This is used to scan the integrity of the file system as well as the hard disk. It is always possible that your error message stemmed out from any physical problem with the hard disk.
- Then you need to use the system file checker utility. This is used to scan and fix any corrupted system files. It is unlikely that the steps we have talked on shall cause problems with system files but it is possible as well. It is quite easy to check on and fix.
As such error messages can be a bit intimidating as they pop up, this is because of the little information user is given when they appear, these are easy to repair. The user just needs to know what to look for and have the recovery solution ready to load.
I hope the above has helped you fix the BCD bootrec errors you have been seeing. We use a varitey of EFI shell commands in CMD to repair the bootloader. Let me know if there is an alternative method you know of that can be mentioned above.