Fix BitLocker STATUS_FVE_FS_MOUNTED Error 0XC0210007

You're stuck with 'This operation cannot be performed while a file system is mounted' error.

I know that feeling — you're trying to lock or manage a BitLocker-protected drive, and Windows throws up this cryptic error code 0xC0210007. It's not a hardware failure, it's not a corrupt drive. The fix is simple: the volume you're trying to act on is still mounted by Windows, so BitLocker won't touch it.

The one fix that works 99% of the time: dismount the volume

Here's what you do. Open Command Prompt as Administrator. Click Start, type cmd, right-click Command Prompt, select 'Run as administrator'.

First, find the drive letter or volume number that's giving you trouble. Type:

manage-bde -status

You'll see a list of volumes. Look for the one with the error. Let's say it's drive D:. Now, you need to dismount it. Type:

manage-bde -lock D: -ForceDismount

After you hit Enter, you should see a message like 'The volume was successfully locked.' If you get an error about the drive being in use, add -ForceDismount again (yes, it's safe for system drives if you're careful — but never dismount your boot drive, C:).

Now try whatever BitLocker operation you were doing — unlocking, changing PIN, suspending protection. It should work now.

Why this happens — and why the fix works

BitLocker is designed to protect data at rest. When a volume is mounted, Windows has an open file handle to it. BitLocker sees that handle and refuses to lock or modify the volume's encryption state because doing so could corrupt data or cause a crash. The -ForceDismount flag tells Windows to close all open handles to that volume. After that, BitLocker can safely do its job.

This error usually shows up when:

• You just unlocked the drive and tried to lock it again too fast.
• An app (like a backup tool or antivirus) has a file open on the drive.
• You're trying to change BitLocker settings through PowerShell or GUI while Explorer has the drive open.

The real-world trigger I see most often is someone unlocking their USB drive, then immediately trying to lock it or change the password. Windows hasn't released the mount yet. The -ForceDismount solves it every time.

Less common variations of this issue

Sometimes you'll get this error on a data drive (like D: or E:) after a reboot. Windows automatically mounts all fixed drives, and BitLocker locks them. But if you try to manually lock a drive that's already locked (because of Auto-Unlock), you'll see 0xC0210007. In that case, skip the manual lock — just unlock it and use it normally.

Another variation: the error appears when you're using manage-bde -protectors -disable on a drive that's currently decrypted and mounted. The fix is the same — dismount first — but you might need to close File Explorer windows pointing to that drive. A quick way: open Task Manager, find Windows Explorer, right-click and choose 'Restart'. That unmounts all drives temporarily. Then run your BitLocker command.

If you're scripting this with PowerShell, the equivalent is:

$volume = Get-BitLockerVolume -MountPoint "D:"
Disable-BitLocker -MountPoint "D:" -ForceDismount

I've also seen this happen when a drive is part of a Storage Space or is shared over the network. The file system stays mounted because another machine is accessing it. Disconnect the network share first, then dismount.

How to prevent this from happening again

Simple habits stop this error cold:

• Before running any BitLocker command, close all open files and folders on that drive. Yes, even if you think they're closed.
• If you use BitLocker on removable drives, always eject the drive safely (right-click in File Explorer, choose 'Eject') before physically removing it. That forces a dismount.
• When scripting BitLocker operations, always include a -ForceDismount flag as a safety net. It won't hurt if the volume is already unmounted.
• If you're using Auto-Unlock on a data drive, don't try to manually lock it. Windows handles that for you at shutdown.

One more thing: if you ever see this error on your C: drive, stop. Do not try to dismount C: — you'll crash the system. That error on the boot drive usually means something went wrong with the Boot Configuration Data (BCD). In that case, boot from a Windows recovery USB and run bootrec /fixboot from the command prompt.

That's it. The fix is one command, it takes 10 seconds, and you're back in business.