What to look at:

  • SATA/NVMe drive failing or cable loose.
  • Boot mode mismatch (UEFI vs Legacy) after a reset.
  • Boot order changed; the OS drive fell behind USB/DVD.
  • Damaged bootloader; needs repair via recovery media.
  • Recent clone to SSD missing EFI partition.

Need help? Check here: /services/repairs/

What it might be (likely causes)#

  • Storage not detected or failing
    A loose SATA cable, unseated NVMe, or a dying drive can disappear from firmware. If the drive isn’t listed in BIOS/UEFI, the OS can’t boot. If it is listed but throws the error, suspect the bootloader/partitioning.

  • Boot mode mismatch (UEFI vs Legacy/CSM)
    Windows installed in UEFI/GPT won’t boot in Legacy/MBR mode and vice versa. A CMOS reset can flip this setting. Background: UEFI, MBR vs GPT

  • Boot order drift
    After firmware updates or adding drives, the boot order may rank a USB stick or empty device first. Set the OS drive (or “Windows Boot Manager”) back to the top. If you need brand keys and boot-UI tips: /posts/boot-from-usb-every-major-system/

  • Broken bootloader
    Power loss or disk issues can corrupt the bootloader. Windows repair tools (bootrec, bcdboot) can rebuild it. Reference: Microsoft bootrec/bcdboot

  • Imperfect clone/migration
    A clone that skipped the EFI System Partition (ESP) or marked partitions wrong will boot to this error. Verify the ESP exists and is flagged correctly. Migration prep tips: /posts/prepare-for-computer-repair/ and backups: /posts/simple-data-backups-without-cloud/

Things to check (quick, safe wins)#

  1. See if the drive exists in firmware
    Enter BIOS/UEFI (F2, Del, F10 vary by brand). If the drive isn’t listed, reseat cables (SATA data + power) or the NVMe stick. If still absent, the drive may be failing.

  2. Confirm boot mode matches the install

    • If Windows was installed as UEFI, ensure UEFI mode is enabled and CSM/Legacy is disabled.
    • If it was Legacy/MBR, enable Legacy/CSM (temporary) to boot and plan a proper migration later. General boot thinking: /posts/the-art-of-making-things-boot/

  3. Fix boot order
    Put Windows Boot Manager (for UEFI) or the correct drive (Legacy) at the top. Remove USB/DVD from first place while testing.

  4. Run a quick drive health check
    If firmware sees the drive, boot a Windows installer or recovery USB → Repair your computer → Command Prompt and run:

    chkdsk C: /scan

    Any ugly errors? Back up first if possible.

  5. Repair the bootloader (Windows)
    From recovery Command Prompt (UEFI install):

    bootrec /scanos
bootrec /fixmbr
bootrec /fixboot
bootrec /rebuildbcd
bcdboot C:\Windows /l en-us /s S: /f UEFI

    Note: Replace S: with your EFI partition letter (assign one with diskpart if needed). Microsoft reference: Repair the boot menu

  6. Verify the EFI System Partition exists
    Use diskpart → list vol. Look for a small (~100–300 MB) FAT32 partition (ESP). If missing after a clone, recreate/copy it, then rerun bcdboot.

  7. If the drive is failing, stop and back up
    SMART warnings or missing drives that reappear intermittently point to imminent failure. Image the disk to a healthy SSD before more experiments: /posts/simple-data-backups-without-cloud/

Patterns that narrow it down#

  • Drive not in BIOS/UEFI at all → physical connection or failed drive.
  • Drive present, “Windows Boot Manager” missing → bootloader/ESP issue.
  • Error appeared after CMOS reset → UEFI/Legacy mode mismatch or boot order.
  • After cloning to SSD → missing/incorrect ESP or wrong partition flags.

If you’re considering a sturdier, low-drama setup after recovery, a Linux conversion can be a clean slate on older PCs: /posts/linux-distros/ and local EOL context: /posts/windows-10-end-linux-kirksville/

When to pause and get hands-on help#

  • The drive vanishes intermittently or SMART attributes are worsening.
  • Bootloader repairs loop or error out, or bcdboot can’t find Windows.
  • You need to salvage files before fixing boot.
    Bench testing with spare cables, cloning tools, and a controlled recovery environment will save your data and time.

Insight#

“No boot device” isn’t a verdict—it’s a map. Either the device isn’t there (power/cable/drive), the firmware can’t hand off correctly (mode/order), or the loader is missing. Solve it in that order: see the drive, match the mode, rebuild the loader. If storage is suspect, protect data first; computers are replaceable, your files aren’t.

Need a precise recovery, clone, or boot repair in Kirksville?
See /services/repairs/.