Hello everyone here is a very simple fix for the error message cannot find BOOTMGR.

I have some considerable experience with computer problems. I also ran into this error message cannot find bootmgr problem along with many others. I have the solution below to fix the problem. It took many many hours before I discovered an easy way to fix it, and I also discovered how it happened.

The problem occurs when a PC or a Laptop is rebooted while connected to other devices such as mobile phones or external hardrives. It is something to do with a clash between certain types of hardrive taking priority over drive and storage devices. A file is dumped in the wrong place or on the wrong drive on reboot or restart of the machine. When the machine finishes the reboot sequence the machine cannot find the file required to start up and an error message will appear saying "cannot find bootmgr".

To solve this problem in the easiest manner within a few minutes follow the simple instructions.

To experienced computer users all you need do is enter your bios and allow only your C: Drive to be bootable. All other computer users please follow the instructions as given.

The computer BIOS can cause your computer damage if some settings are set incorrectly. If you are reading this?  I would suggest only making the changes as show here to avoid bios setting problems.

To enter the bios you must reboot. While the computer is beginning to reboot press the F2 key to enter the bios. If you miss it then reboot again and keep pressing the F2 until you get into the bios. Note some computers use a different key to enter bios example DELETE KEY.

When you get into the bios, there should be an example of how to navigate around the bios controls. This varies from pc to pc but normally the arrow keys, are a part of the navigation controls. You need to navigate to the BOOT section of the bios and disable all devices from boot option apart from the C Drive. Save and exit the bios.

The computer will now reboot into windows, it can no longer favour a different drive to try and boot from where the start up files are missing.

Your computer is now fixed!