The reason for this post is that it took me three hours on the weekend to fix this problem and based on the amount of search results the Google returns for that keywords I figured there are a lot of people facing such a problem. So my goal is to provide with a simple explanation and easy fix to save one's time and may be even prevent this problem from happening.
Let's start first from understanding what exactly is the problem. Secondly we see how to fix it and lastly we discuss the scenarios that could cause such a problem.
There is an important condition for the fix described in this article: the computer was booting before but after some changes this error occurred. If this is not the case than the solution might not be applicable but from another hand it would not hurt to read further.
So what exactly is the problem? The answer is easy: it's right in the message. Windows is looking for a file with a name "bootmgr" and cannot find it. This is a hidden file of a size about 320Kb that should reside in the root of a boot partition on a hard drive where the Windows OS is installed. We will discuss the reasons why it's missing later but now since we know what the problem is how can it be fixed?
Another set of reasons relate to hardware problems with hard drives and not covered in this post for an obvious reason that the only solution for that is to replace a hard drive and reinstall Windows.
Let's start first from understanding what exactly is the problem. Secondly we see how to fix it and lastly we discuss the scenarios that could cause such a problem.
The problem
When one tries to boot up a computer with Windows 7 OS on it and instead sees a black screen with a message "Bootmgr is missing - Press CTRL+ALT+DEL to restart". (I guess it's obvious that restarting will not fix the problem)There is an important condition for the fix described in this article: the computer was booting before but after some changes this error occurred. If this is not the case than the solution might not be applicable but from another hand it would not hurt to read further.
So what exactly is the problem? The answer is easy: it's right in the message. Windows is looking for a file with a name "bootmgr" and cannot find it. This is a hidden file of a size about 320Kb that should reside in the root of a boot partition on a hard drive where the Windows OS is installed. We will discuss the reasons why it's missing later but now since we know what the problem is how can it be fixed?
The fix
Copy the bootmgr file from the source to the root of the boot Windows partition on hard drive. An XCOPY command can be used with an /h switch that allows copying hidden and system files. For example:X:/>xcopy bootmgr C:\ /hWhere to find the bootmgr file?
This is an important question. The answer depends on a particular computer's configuration but based on the problem statistics let's just mention the most probable locations to search for the file (don't forget it's hidden):- Root of another hard drive with Windows 7 on it
- Root of another partition on the same hard drive with Windows 7 on it
- Windows 7 installation DVD
The possible causes of the problem
In my case and based on the Internet search results that seems to be a very popular cause I have installed a second hard drive in the computer and then installed Windows 7 on a new hard drive. The key here is that Windows installer did not copy the bootmgr file on a new hard drive because it already existed on an old hard drive. The same problem would have happened if Windows was installed on a new partition on the same hard drive where another Windows installation present. These two reasons cover over 80% of the problem occurrences with some variations around different versions of Windows that existed at the moment of a new Windows installation and dual-boot related problem with the same outcome.Another set of reasons relate to hardware problems with hard drives and not covered in this post for an obvious reason that the only solution for that is to replace a hard drive and reinstall Windows.