BOOTMGR and NTDRL are some of the most essential files that a computer requires in order to boot safely, without which the computer cannot boot. Which are also the most vulnerable documents in case of a hard disk damage.
This two problems are similar in the way they present themselves, how they affect the computer and probably even in their causes.
There are several cause to this problem:
- Incorrect boot device.
- Lack of an OS in your hard disk.
- corrupt data on a hard disk
- incorrect active partition.
If your computer keeps failing to boot returning an error:
- “NTDRL is missing press Ctrl+ Alt+ Del to restart,” or
- “BOOTMGR is missing press Ctrl + Alt + Del to restart,”
there is probably a boot file missing in your computer, or in the partition for which you want to boot your OS from.
Both problems are mainly caused by the user. During the process, the user will continue to use their computers. However, once they restart their computers, they then start to face the errors again.
How to fix these problem causes.
There are two probable causes for this failure. In each cause the user will have to undertake different measures in order to do away with the problem.
I am going to start the diagnostics from the easiest problem to deal with up to the worst probable cause in order to allow the user to be able to diagnose the problem properly. And also for the users safety to save their data.
1. Wrong active partition.
An active partition is a partition from which you are supposed to boot your windows from. For example a partition on which windows is installed on or a system reserved partition.
However, for your own safety, it is always wise not to set an active partition on your hard disk partitions. If you set a partition active, whereas there is no boot data installed on the partition, Windows will certainly not be able to install.
The solution to this problem is simpler than all the other solutions for the rest of the problems.
However, you will be required to have a bootable installation media, since we are going to be using the CMD to restore the active partition.
- Install the install media into the computer, and press the Ctrl + Alt +Del to restart the computer.
- Make sure that the computer boots using the bootable media. Press the function key F9 to select the boot media.
- When the computer boots and the blue windows installation screen appears, click on the button Repair your computer, and another screen appears with several options to repair your computer.
- Open the control panel and type the command DISKPART. You will have opened a software to control your hard disk partitions.
- Enter the command LIST VOLUME. A list of all the partitions on your hard disk will appear, and make sure you note the number assigned to the hard disk partition on your computer in which windows is installed on. By default, this should be on C.
- Highlight the partition, enter the command SELECT VOLUME #.
- Enter the command ACTIVE to change the boot partition.
Reboot your computer and see if the problem is fixed.
If your problem is not fixed, repeat the process one more time. If the problem persist, move on to the second diagnostic.
2. Tampering with boot data.
First of all never delete any data on your hard disk with an extension .sys. These are the system files that the computer uses to boot up your computer. However, all the system files in a computer, are stored in hidden form. There is no way you can be able to read, or write a system file.
Restoration of deleted or tampered boot data may be quite troublesome.
In order to do away with this problem, you will be required to have a bootable installation media, and probably a backup of your computer.
- Boot up your computer using the installation media like we did before while diagnosing a problem in the active partition.
- When the blue windows installation screen appears, select the button Repair your computer, and another screen will appear.
- Select the option to restore your computer previous state, and restart the computer.
- Instead of selecting the option to restore your computer, open the control panel, and type in the command SFC / scannow.
If this procedure does not work, you would have to reinstall your Windows all over again.
Another option can be if there is no OS installed on your computer (Maybe you formatted your hard disk,) in which case you may also be forced to reinstall your windows.