Repair “A required device isn't connected or can't be accessed” errors

Windows Boot Manager reaches the Recovery screen but cannot locate or access the device, partition, volume, boot object, or Windows loader referenced by the boot configuration. The most common searchable presentation is error code 0xc0000225 with A required device isn't connected or can't be accessed.

Searchable Windows error codes and exact messages

Useful exact-message searches include A required device isn't connected or can't be accessed, The application or operating system couldn't be loaded because a required file is missing or contains errors, and the complete File: value from the screen. The same code can result from an absent drive, wrong BCD reference, missing EFI System Partition, unreadable file system, or failed storage path. The code alone does not choose the repair.

Use this procedure when the Windows disk is consistently visible, the intended Windows volume is readable in Windows Recovery Environment, and the existing system partition can be detected. It is most useful after cloning, partition work, removal of a second disk, or a boot configuration change.

Do not use this procedure when the Windows disk is absent from firmware or repeatedly disappears, when the EFI System Partition was deleted or formatted, when the screen names a corrupt registry hive, or when hardware diagnostics report a fault. Use FIX-005 for a missing drive and the dedicated EFI-partition reconstruction procedure for a deleted EFI System Partition.

The exact Windows build, motherboard model, and original event that changed the reference may remain unknown. The Windows volume, disk partition style, system partition, and currently used boot path may not remain unknown.

• Windows Recovery Environment or Windows 10/11 installation media
• Command Prompt
• A consistently detected Windows disk
• A readable Windows volume and existing system partition
• Free space on the Windows volume for boot-configuration backups

Select Repair your computer > Troubleshoot > Advanced options > Command Prompt. In the commands below, W: represents the detected Windows volume and S: represents the detected system partition. Assign those letters only after inspection.

1. Record the complete Recovery screen, including its code and File: line.

2. Inspect the available disks and volumes:

   diskpart
   list disk
   list volume
   

3. Locate the already-identified Windows volume by its size, file system, label, and contents. If it has no usable letter, select it by number and assign W:

   select volume <Windows-volume-number>
   detail volume
   assign letter=W
   

4. Confirm the installation rather than relying on the volume label:

   dir W:\Windows\System32\Config\SYSTEM
   dir W:\Windows\System32\winload.*
   

5. Return to DiskPart and map the Windows volume to its physical disk:

   diskpart
   select volume <Windows-volume-number>
   detail volume
   select disk <Windows-disk-number>
   list partition
   

6. Detect the boot layout:

   • A GPT disk and small FAT32 EFI System Partition indicate UEFI boot.
   • An MBR disk and NTFS System Reserved or active system partition indicate BIOS/MBR boot.
   • Do not ask the reader to guess the firmware mode; derive it from list disk, the partition style, and the system partition.

7. Select the detected system partition, inspect it, and assign S:

   select partition <system-partition-number>
   detail partition
   assign letter=S
   exit
   

8. On UEFI/GPT systems, inspect the boot files and BCD store:

   dir S:\EFI\Microsoft\Boot
   bcdedit /store S:\EFI\Microsoft\Boot\BCD /enum all /v
   

9. On BIOS/MBR systems, use:

   dir S:\Boot
   bcdedit /store S:\Boot\BCD /enum all /v
   

10. Record each Windows loader's identifier, device, osdevice, path, and systemroot. If the store points to an absent disk, removed partition, or wrong Windows directory, the diagnosis is confirmed.

11. If the correct disk or volume is not readable, stop. Recreating BCD entries cannot repair a disappearing device or a failing I/O path.

UEFI/GPT branch

1. Create a backup directory:

   md W:\BootRepairBackup
   

2. Preserve the existing BCD store when readable:

   copy S:\EFI\Microsoft\Boot\BCD W:\BootRepairBackup\BCD-before-0xc0000225-repair
   

3. Recreate the boot files and BCD references from the verified Windows installation:

   bcdboot W:\Windows /s S: /f UEFI /v
   

4. Confirm that BCDBoot reports Boot files successfully created. If it reports a copy or source error, stop and recheck W:, S:, free space, and file-system health.

5. Re-enumerate the repaired store:

   bcdedit /store S:\EFI\Microsoft\Boot\BCD /enum all /v
   

6. Confirm that the Windows loader now points to the intended Windows volume and \Windows\System32\winload.efi.

7. Restart and test. If the boot files are correct but the firmware has no Windows Boot Manager entry, return to WinRE and refresh the firmware entry while preserving existing boot order:

   bcdboot W:\Windows /p /v
   

8. Restart twice after a successful repair.

BIOS/MBR branch

1. Create the backup directory and preserve the readable store:

   md W:\BootRepairBackup
   copy S:\Boot\BCD W:\BootRepairBackup\BCD-before-0xc0000225-repair
   

2. Recreate BIOS boot files on the detected system partition:

   bcdboot W:\Windows /s S: /f BIOS /v
   

3. Restart and test twice.

4. Do not change Active flags unless DiskPart proves that the wrong MBR partition is active. That is the separate BP-004 condition.

• BCDBoot succeeds and Windows starts: The missing or stale device reference was repaired.
• BCDBoot succeeds but the identical error returns: Firmware may be using a different ESP or system disk. Re-enter WinRE and identify the partition that firmware actually uses.
• The Windows disk was previously booted through a second disk's ESP: Keep the second disk disconnected and place boot files on the intended disk's existing system partition.
• No suitable system partition exists: Stop. Do not shrink, create, format, or retype a partition under this procedure.
• The code changes to a named file error: Follow the named file. Use FIX-013 for winload.efi, FIX-017 for the SYSTEM hive, or FIX-018 for a checksum mismatch.
• The drive disappears or reports repeated I/O errors: Stop Windows repair and investigate storage, cabling, slot, power, or controller hardware.

• Do not assume WinRE assigned Windows the letter C:.
• Do not format the EFI System Partition or System Reserved partition.
• Do not create boot files on the first FAT32 partition merely because it is FAT32.
• Do not run bootrec commands indiscriminately.
• Do not rebuild BCD when the disk itself is absent or unstable.
• Do not delete an existing ESP on another disk until the repaired disk starts independently twice.

If the new BCD removes an intentional loader, preserve the new store, then copy the saved BCD back to its original path. A restored store may also restore the broken device reference, so use rollback only to recover intentional entries or compare configuration.

For UEFI:

copy /y W:\BootRepairBackup\BCD-before-0xc0000225-repair S:\EFI\Microsoft\Boot\BCD

For BIOS/MBR:

copy /y W:\BootRepairBackup\BCD-before-0xc0000225-repair S:\Boot\BCD

• Windows starts normally twice with nonessential disks disconnected.
• bcdedit /enum all /v works from the running Windows installation.
• The loader's device, osdevice, path, and systemroot match the intended installation.
• The computer no longer displays 0xc0000225 or 0xc000000e.
• Reconnecting data disks does not change which disk supplies the boot files.

Confidence is approximately 85% when the Windows disk is stable, both required partitions are detected, and BCD inspection proves a stale or missing device reference. Stop when the drive is unstable, more than one plausible system partition exists, no system partition exists, or the displayed file points to a different failure mechanism.