A machine that shows no boot device or drops into recovery usually has a damaged boot record, not a dead disk. bootrec and bcdboot rebuild the parts separately, and each command has a different job.
From WinRE, run **bootrec /scanos**, then **bcdboot C:\Windows /s S: /f UEFI** to rebuild the boot files, and **bootrec /rebuildbcd** to register the installation. Check the disk with **chkdsk** before trusting either.
Recovery letters differ from the running system. **diskpart** shows the real layout, and the Windows folder tells you which letter is the installation.
reagentc /info
wmic logicaldisk get deviceid,volumename,size
for %d in (C D E F) do @if exist %d:\Windows\System32\winload.exe echo %d is WindowsA failing disk produces the same symptoms as a broken boot entry. **chkdsk** finds bad sectors and file system damage that no boot command can fix.
chkdsk C: /f /r
diskpart /c "list volume"
Get-PhysicalDisk | Select-Object FriendlyName,MediaType,HealthStatus,OperationalStatus**bcdboot** copies the boot manager from the Windows folder to a system partition. On UEFI systems the target partition must be FAT32 and the firmware type must be UEFI.
diskpart /c "select volume S"
diskpart /c "assign letter=S"
bcdboot C:\Windows /s S: /f UEFI
bcdboot C:\Windows /s S: /f ALL**/fixmbr** rewrites the boot code, **/fixboot** writes a new boot sector. Both matter only for BIOS or MBR installations; on GPT with UEFI they are harmless but not the fix.
bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd**bcdedit /enum** must list a Windows Boot Manager with a device and a timeout. An empty store means bcdboot wrote to the wrong partition.
bcdedit /enum
bcdedit /enum {default} | findstr /i "device osdevice path description"
dir S:\EFI\Microsoft\BootA successful repair boots into Windows and leaves a clean boot log. A failure that repeats points at a driver or a pending update, which the setup and boot logs name.
wpeutil reboot
:: after the boot, if it failed
dir C:\Windows\Panther\*.log
wevtutil qe System /q:"*[System[(EventID=41 or EventID=1001)]]" /c:5 /f:textThe system partition is not FAT32 or has no EFI folder. Format the EFI partition as FAT32 with diskpart, then run bcdboot again.
The boot sector belongs to another volume, or the disk is write-protected. Confirm with diskpart detail disk that the disk attribute is not set to read-only.
Something rewrites the boot entry, usually a second installation or a backup tool. Check the boot order in the firmware and the setup logs for a second entry.
The Windows folder is on a volume the recovery environment cannot read, which points at a missing storage driver. Use a recovery medium with the right driver.
Not always. If Windows still starts far enough, reagentc /boottore or shutdown /r /o opens the same recovery environment from the disk.
No. Startup Repair is an automated attempt; bootrec and bcdboot are the manual steps it tries. Running them by hand shows which one fails.
No. It repairs the boot path. Once Windows starts again, use a file recovery tool before writing anything else to the disk.
bcdboot only writes boot files. To undo it, remove the entry with bcdedit /delete {identifier} or restore a previously exported store with bcdedit /import.
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