Dear Leonardo Schepis,
Thank you for reaching out and providing a detailed description of the issue you're facing. I can understand how frustrating it must be, especially after having installed a customized version of Windows 11. The error code 0xC00000218, which indicates Bad System Configuration Information, typically points to problems with the boot configuration data (BCD) or a corrupt system file.
Here are some suggestions you can try to resolve the issue:
1. Perform Startup Repair:
Since your system is unable to start normally, you can try performing a Startup Repair through the Windows Recovery Environment (WinRE).
- Power off your PC completely.
- Turn it back on and, as soon as the manufacturer’s logo appears, force a shutdown by pressing and holding the power button for 10 seconds.
- Repeat this process three times to trigger WinRE (Windows Recovery Environment).
- Once in WinRE, go to Troubleshoot > Advanced options > Startup Repair.
- Allow Windows to attempt to repair the startup issue automatically. If successful, your system should boot normally.
2. Rebuild the Boot Configuration Data (BCD):
Since the error involves the Bad System Configuration Information, you may need to manually rebuild the BCD. Here’s how to do it:
- Boot into WinRE using the steps mentioned above.
- Once in WinRE, go to Troubleshoot > Advanced options > Command Prompt.
- In the Command Prompt window, type the following commands one by one, pressing Enter after each: bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd
- After running these commands, close the Command Prompt and restart your system.
If none of the above suggestions resolve the issue, and you suspect that the customized Windows 11 OS might be causing instability, it may be best to reinstall a clean version of Windows 11.
Create an installation media
Go to the official Microsoft Windows 11 download page.
Under the Create Windows 11 Installation Media section, click Download now.
Run the downloaded MediaCreationToolW11.exe.
Read and accept the Microsoft license terms.
Select the language and edition that matches your product key (if necessary, you can use the recommended options for this PC).
Select USB flash drive as the media type and click Next.
Choose your USB drive from the list and click Next. The tool will download Windows 11 and create the installation media.
Wait for the process to complete. This may take some time depending on your internet speed. Once done, you will have a bootable USB drive with Windows 11.
Adjust startup priority
Insert the USB flash drive into the computer where you plan to install Windows 11.
Restart the computer and enter the BIOS/UEFI settings. This is usually done by pressing a key like F2, F10, DEL, or ESC repeatedly during startup (consult your motherboard or laptop manual for the correct key).
In the BIOS/UEFI settings, navigate to the boot menu and set the USB drive as the primary boot device.
Save the changes and exit the BIOS/UEFI settings. The computer will reboot and begin booting from the USB drive.
Install
Select your language, time and currency format, and keyboard layout, then click Next.
Click the Install now button.
Enter your Windows 11 product key. If you don’t have one, you can select I don’t have a product key and activate Windows later.
Choose the edition of Windows 11 that corresponds with your license (usually, this will match what you already installed).
Select Custom: Install Windows only (advanced).
You will see a list of your disk partitions. To perform a clean install, delete all existing partitions on your system drive:
Select each partition, then click Delete, and confirm.
Be very careful to select the correct drive and partitions as this will erase all data on the selected partitions.
Once all partitions are deleted, you should have an unallocated space.
Select the unallocated space and click New. This will create a new partition.
Click Apply and confirm to use the maximum space.
Windows will create several partitions for system files automatically. Select the primary partition (usually the largest one) and click Next.
The installation process will begin, copying and installing Windows 11 files. This will take some time, and your computer may restart several times. (Unplug USB drive)
After installation is complete, Windows 11 will restart and start the initial setup process.
Important Note:
Since you've mentioned that you're using a customized Windows 11 OS from a third-party source, there's a possibility that it might be causing conflicts or instability with your system. I recommend using an official version of Windows 11 to avoid any further complications. Although you mentioned that it hasn't had problems before, that doesn't mean it's always been stable and reliable, it's had stability issues to a greater or lesser extent.
If you're still experiencing difficulties, please let me know, and we can continue troubleshooting together.
Best Regards,
Martin | Microsoft Community Support Specialist