On detecting boot failure, Windows Vista and Windows 7 computers automatically fail over and loader generally launches Windows Recovery Environment (Windows RE) instead of the operating system. This fail over mechanism is dependent on Windows boot loader and Windows boot manager. In some situations, when these metadata structures are also unreadable, Windows RE itself can become inaccessible to the user. Because such situations won't allow you to boot to your computer, they can bring serious data loss in case no suitable data backup is available for Windows Data Recovery.

Before describing the probable causes and solutions of such problems, let's first describe the problem with an associated example. Suppose you use a Windows 7 computer and for some reasons, you cannot boot into your computer. Thus, to resolve the issue, when you try to start Windows Recovery Environment, it doesn't succeed. Unlike your expectations, Windows Boot Manager screen appears and the below error message is displayed at the bottom of the screen:

“Windows failed to boot because a required device was inaccessible”,0x0000225C

Since you cannot start Windows RE, Windows 7 boot failure problem remain unfixed.

Explanation of the behavior

The above situation can result if any of the following situations is true:

Boot Manager is corrupt or missing Boot Configuration Data is missing or corrupt Disk metadata in MBR (Master Boot Record), boot sector of Windows RE partition, or partition table is corrupt

Steps to Resolve the Issue

To isolate this specific issue, you need to boot Windows using bootable Windows RE media and perform one or more of the following steps:

Use Windows RE media to start the computer and run 'Startup Repair' Fix the boot loader issue using Bootrec.exe utility

If none of these solutions works, erase the Windows partition, reinstall Windows from scratch, and perform Windows Data Recovery from last available backup. As an alternative to data backup, you can also use a Partition Recovery tools that can scan a logically crashed disk and recover data from missing, lost, corrupted, deleted, or formatted Windows partitions.

Stellar Phoenix Windows Data Recovery is a comprehensive utility designed for recovering lost partition data from Windows 7, Vista, XP, 2003, and 2000 based computers. Incorporated with high-end Partition Recovery algorithms, this software can scan your disk and recover most of the data with just a few clicks.