After upgrading my 2015 MBP to Sierra this past weekend, I've had a lot of issues with Samba, Veracrypt, and even VMware Fusion.

VeraCrypt will frequently give the error in the title, mount_osxfuse: the OSXFUSE file system is not available (255), when I attempt to mount a valid encrypted volume. There's nothing wrong with the volume itself, and sometimes if I reboot, I can get VeraCrypt to work properly, but it's certainly touch and go.

OSXFUSE documentation and googling hasn't suggested any fixes for this issue.

I've attempted to uninstall and reinstall OSXFUSE without any luck. Whether it works or not seems random after restarts. Obviously, restarting this often sucks. I restarted on average 3-4 times a year on Yosemite, and I've restarted about a dozen times since upgrading to Sierra dealing with these problems. I'd like to know if there's a permanent fix for this, otherwise I'll be dealing with my encrypted volumes on a Win 10 VM (when VM Fusion works, anyway...yeesh).

3 Answers 3


The following script from this link fixes the problem: https://github.com/osxfuse/osxfuse/issues/315

I called this kextclean:


function status() {
    kextstat | grep org.virtualbox.kext > /dev/null 2>&1 ;
    kextstat | grep com.github.osxfuse > /dev/null 2>&1 ;


if [ "$1" == "vbox" ] ; then
    if [ $vbox == 1 ] ; then
    echo "Already vbox"
        sudo kextunload -b com.github.osxfuse.filesystems.osxfuse
        sudo kextutil "/Library/Application Support/VirtualBox/VBoxDrv.kext" -r "/Library/Application Support/VirtualBox"
        sudo kextutil "/Library/Application Support/VirtualBox/VBoxNetAdp.kext" -r "/Library/Application Support/VirtualBox"
        sudo kextutil "/Library/Application Support/VirtualBox/VBoxNetFlt.kext" -r "/Library/Application Support/VirtualBox"
        sudo kextutil "/Library/Application Support/VirtualBox/VBoxUSB.kext" -r "/Library/Application Support/VirtualBox"
elif [ "$1" == "fuse" ] ; then
    if [ $fuse == 1 ] ; then
    echo "Already fuse"
        sudo kextunload -b org.virtualbox.kext.VBoxUSB -b org.virtualbox.kext.VBoxNetFlt -b org.virtualbox.kext.VBoxNetAdp
        sudo kextunload -b org.virtualbox.kext.VBoxDrv
        sudo kextutil /Library/Filesystems/osxfuse.fs/Contents/Extensions/10.12/osxfuse.kext
elif [ "$1" == "status" ] ; then
    echo "vbox = $vbox"
    echo "fuse = $fuse"
    echo "Run $0 <vbox|fuse|status>"
  • thanks so much for sharing this answer 🙏, i've come back to this sh script several times now.
    – ipatch
    Feb 19, 2021 at 2:37

The command

sudo kextutil /Library/Filesystems/osxfuse.fs/Contents/Extensions/10.12/osxfuse.kext

did fix the problem. TrueCrypt is working again.

  • 1
    This didn't work for me, I got a "Error Domain=KMErrorDomain Code=71 "Kernel request failed: (libkern/kext) kext (kmod) start/stop routine failed (-603946985)" UserInfo={NSLocalizedDescription=Kernel request failed: (libkern/kext) kext (kmod) start/stop routine failed (-603946985)}" Error. :-( But thanks for the suggestion.
    – csgeek
    Mar 14, 2021 at 16:31

TLDR: restarting my Mac got rid of the "mount_osxfuse: the file system is not available (255)" error for me.

I have TrueCrypt 7.1.x but I also installed VeraCrypt 1.21 for continuity. VC requires OSXFUSE 2.5, but I had OSXFUSE <2.5 and so I hit 'upgrade' within System Preferences, to what turned out to be 3.7.1. When I did this, I saw a flavor of the "mount_osxfuse: the file system is not available (255)" error when trying to mount with either VeraCrypt or with TrueCrypt.

The upgrade may be a coincidence, but I had also hit 'Eject' using Finder on my Volume, which I think may have caused the problem.

The intended use is to "Dismount" within TrueCrypt/VeraCrypt instead. Oops. But after restarting, all was well. That's about all the investigating I did.

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