Description of problem:
I tried to install LXDE version from LiveUSB and anaconda crashed
The following was filed automatically by anaconda:
anaconda 19.30-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 626, in unmount
    raise FSError("umount failed")
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 792, in teardown
    return self.unmount(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 745, in _preTeardown
    self.format.teardown()
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 757, in teardown
    if not self._preTeardown(recursive=recursive):
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 2786, in findExistingInstallations
    device.teardown(recursive=True)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 420, in reset
    self.roots = findExistingInstallations(self.devicetree)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 140, in storageInitialize
    storage.reset()
  File "/usr/lib/python2.7/threading.py", line 766, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.7/site-packages/pyanaconda/threads.py", line 168, in run
    threading.Thread.run(self, *args, **kwargs)
FSError: umount failed

Version-Release number of selected component:
anaconda-19.30-1.fc19.i686

Additional info:
reporter:       libreport-2.1.4
cmdline:        /usr/bin/python  /sbin/anaconda --liveinst --method=livecd:///dev/mapper/live-osimg-min --lang en_US.UTF-8
cmdline_file:   initrd=initrd0.img root=live:CDLABEL=Fedora-Live-LXDE-i686-19-Beta-1 rootfstype=auto ro rd.live.image quiet  rhgb rd.luks=0 rd.md=0 rd.dm=0  BOOT_IMAGE=vmlinuz0 
core_backtrace: 
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.9.2-301.fc19.i686
other involved packages: python-blivet-0.14-1.fc19.noarch, python-libs-2.7.4-4.fc19.i686
packaging.log:  
product:        Fedora
release:        Fedora release 19 (Schrödinger’s Cat)
type:           anaconda
version:        19

Truncated backtrace:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/pyanaconda/threads.py", line 168, in run
    threading.Thread.run(self, *args, **kwargs)
  File "/usr/lib/python2.7/threading.py", line 766, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 140, in storageInitialize
    storage.reset()
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 420, in reset
    self.roots = findExistingInstallations(self.devicetree)
  File "/usr/lib/python2.7/site-packages/blivet/__init__.py", line 2786, in findExistingInstallations
    device.teardown(recursive=True)
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 757, in teardown
    if not self._preTeardown(recursive=recursive):
  File "/usr/lib/python2.7/site-packages/blivet/devices.py", line 745, in _preTeardown
    self.format.teardown()
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 792, in teardown
    return self.unmount(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/blivet/formats/fs.py", line 626, in unmount
    raise FSError("umount failed")
FSError: umount failed