How to fix the Windows 2008 R2/2012 R2 BOOTMGR is missing error

How to Fix and Repair Computer Errors and Problems

Here are few steps you can try to fix the missing bootmgr:

  1. Boot from Windows installation CD and select Repair then Command Line tools and type the following command line:
    BCDBoot C:\Windows
  2. If any of the first method did not help, then type this command lines:
    bootrec /fixmbr
    bootrec /fixboot
    bootrec /rebuildbcd
  3. If none of this helps then try to run the Windows repair or restore a backup in case you have one.
  4. If any of above did not fix the problem then you may have to re-install Windows.

We also recommend reading this book.