The most common reasons for BOOTMGR errors include corrupt and misconfigured files, hard drive and operating system upgrade issues, corrupt hard drive sectors, an outdated BIOS, and damaged or loose hard drive interface cables. On most Windows computers, this partition is labeled as System Reserved and doesn’t have a drive letter. It is located in the root directory of the partition marked as Active in Disk Management.
The BOOTMGR file itself is both read-only and hidden. Click the Repair your computer option after selecting your language, time and keyboard method. To fix BOOTMGR is missing in Windows 7 without CD, you can create a bootable USB from ISO and then boot the PC from the USB drive to enter the Windows Recovery Environment. How do I fix Bootmgr is missing in Windows 7 without CD?
