Fix NS_E_BAD_FSMAJOR_VERSION (0XC00D0065) on Windows 10/11

I know seeing that NS_E_BAD_FSMAJOR_VERSION (0XC00D0065) error is infuriating — especially when you're just trying to access a disk that worked fine yesterday. This tripped me up the first time too. But the fix is straightforward, and I'll walk you through it step by step.

What triggers this error

This error usually shows up on Windows 10 or 11 when you plug in an external drive, upgrade your OS, or move a disk from an old Windows Media Center setup. The disk's file system — like NTFS or FAT32 — has a major version that Windows doesn't support. Think of it like trying to read a book in a language your brain forgot. Real-world example: I saw this on a Toshiba Canvio external drive after a Windows 11 22H2 upgrade.

The fix: Reformat the disk

Skip the registry hacks and driver reinstalls — they don't help here. The real fix is to reformat the disk. Warning: this wipes all data on that drive. If you need the data, recover it first using a tool like EaseUS or Recuva on a different PC.

1. Open Disk Management: Right-click the Start button and select Disk Management.
2. Find the disk with the error — it'll show as RAW or with a weird file system. Don't confuse it with your system drive (C:).
3. Right-click the partition and select Delete Volume. If it's greyed out, use Diskpart from Command Prompt.

Using Diskpart (faster):

diskpart
list disk
select disk X   (replace X with the problem disk number)
clean
create partition primary
format fs=ntfs quick
assign letter=Y

Replace X with your disk number. The clean command wipes everything — make sure it's the right disk.

Why this works

The error occurs because Windows can't read the file system's metadata — specifically the major version field. By formatting with format fs=ntfs, you write a fresh NTFS header that Windows 10/11 understands. Version 3.1 is the current standard.

Less common variations

Sometimes the error pops up on internal drives after a failed OS upgrade. If you can't format because it's your boot drive, you need to boot from a Windows installation USB, press Shift+F10 to open Command Prompt, and run Diskpart there.

Another rare case: a drive formatted with exFAT on a Mac or Linux box. Windows sometimes gets confused by the major version. Run fsutil fsinfo volumeinfo X: to check the file system version. If it's not NTFS 3.1 or FAT32, you'll need to reformat.

Prevention for next time

• Always eject external drives safely before unplugging.
• Stick to NTFS for Windows-only disks. exFAT is fine for cross-platform use but check compatibility first.
• Before a major Windows upgrade, back up your important data. Don't trust disk converters that promise to upgrade file systems — they often cause this exact error.
• For old Media Center drives, copy everything to a new NTFS drive and retire the old one.

That's it. The error looks scary but it's just a format issue. You won't see it again once you've cleaned and formatted the disk.