loopkid: force unmount on mac os x

force unmount on mac os x

Stefan — Fri, 27 Jun 2008 01:16:00 +0200

When using Mac OS X you might have encountered this message.

The disk "foobar" is in use and could not be ejected.
Try quitting appplications and try again.

This message may occur even if you have all closed all programs. The guilty party for this behavious may be Leopard’s FSEvents, which sometimes has a lock on a volume. To force the unmount of a volume just open a Terminal and use umount.

sudo umount -f /Volumes/FooBar

According to a commentator, if that doesn’t work you can also try

sudo diskutil umount force /Volumes/FooBar

"force unmount on mac os x" by Franck

Tue, 07 Jun 2011 09:22:29 +0200

Many Thanks for your comments. They helped me in fixing application installation problem. Brilliant!!

"force unmount on mac os x" by Donald E. Payne

Thu, 19 Nov 2009 03:12:40 +0100

I found another process that can make a device busy, via the command $ userid root lsof ‘/Volumes/2ndHardrive 1’ COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME fseventsd 76 root 8u REG 14,5 0 1892050 /Volumes/2ndHardrive 1/.fseventsd/000000000038f4c5

fseventsd is a daemon that watches for changes to a mounted volume, for the benefit of applications like Finder and Spotlight. It keeps a file open on the volume, so it is “busy”.

Then I read here http://lists.apple.com/archives/Darwin-dev/2008/Sep/msg00039.html that you are not supposed to use the direct command-line tools like “mount” and “umount” on MacOS, and that “DA [Disk Arbitrator] will notify fseventsd to stop looking”. Surprising to me – I thought MacOS X was basically UNIX.

DA appears to be either a GUI or an API. I want a command line. So I found, via “man -k disk”, the commands “disktool” (deprecated) and “diskutil” as mentioned above. diskutil works when umount fails; I guess it tells fseventsd to stop looking.

"force unmount on mac os x" by RnS

Sat, 24 Oct 2009 00:34:37 +0200

Very helpful, thanks!

"force unmount on mac os x" by Christine Fürst

Sun, 21 Jun 2009 14:34:47 +0200

Hi,

Thanks a lot for this post. It actually solved my problem!

Cheers Christine Fürst (Stinie) from Rotterdam (Netherlands)

"force unmount on mac os x" by Stefan

Fri, 05 Jun 2009 15:30:17 +0200

Okay, so diskutil is mightier than umount on Leopard, right?

"force unmount on mac os x" by mur

Fri, 05 Jun 2009 14:32:31 +0200

the advantage is, that if you cant unmount with anything else you can either take the cable away and hurt external drive or you can unmount with diskutil umount force /Volume/Yourowndisk

"force unmount on mac os x" by Stefan

Sat, 28 Feb 2009 18:24:26 +0100

What’s the advantage of using diskutil over plain umount?

"force unmount on mac os x" by Goatse Man

Fri, 20 Feb 2009 12:36:22 +0100

To force the unmount on OS X 10.5 use

diskutil umount force /Volumes/foobar

"force unmount on mac os x" by Stefan

Fri, 27 Jun 2008 12:30:09 +0200

This works basically the same way on Mac OS X, but sometimes even changing the directory doesn’t resolve the issue,

# umount /Volumes/Foobar
umount: unmount(/Volumes/Foobar): Resource busy

then diskutil comes to the help.

# diskutil umount /Volumes/Foobar
Volume Foobar on disk1s10 unmounted

"force unmount on mac os x" by b.

Fri, 27 Jun 2008 02:34:12 +0200

On linux machines it is often the case, that you are in the mounted directory when trying to unmount the device. Therefore you have to leave the directory to unmount the device:

# mount -o loop foo.iso /mnt
# cd /mnt/bar
# umount /mnt
umount: /mnt: device is busy

The man page tells us: -f Force unmount (in case of an unreachable NFS system). (Requires kernel 2.1.116 or later.)

The -f directive does not work in this case under linux machines. The umount command is still locked. So you have to leave the directory:

# cd /tmp
# umount /mnt