Description of problem:
It happened while trying to reclaim diskspace in order to install Fedora onto a machine running Windows 8. I selected my disk under local standard disk. Under reclaim disk space, I selected an unknown partition, non-Windows partition and upon highlighting said partition, I got the error message that I am not sending.

Version-Release number of selected component:
anaconda-20.25.15-1.fc20.x86_64

The following was filed automatically by anaconda:
anaconda 20.25.15-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python2.7/site-packages/blivet/size.py", line 96, in _parseSpec
    raise SizeNotPositiveError("spec= param must be >=0")
  File "/usr/lib/python2.7/site-packages/blivet/size.py", line 164, in __new__
    self = Decimal.__new__(cls, value=_parseSpec(en_spec, False))
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/lib/disks.py", line 80, in size_str
    size = Size(en_spec="%f mb" % mb)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/lib/resize.py", line 220, in _update_labels
    text = _("Total selected space to reclaim: <b>%s</b>") % size_str(selectedReclaimable)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/spokes/lib/resize.py", line 459, in on_resize_value_changed
    self._update_labels(selectedReclaimable=self._selectedReclaimableSpace)
  File "/usr/lib64/python2.7/site-packages/pyanaconda/ui/gui/utils.py", line 126, in _run_once_one_arg
    self._func(*args, **kwargs)
SizeNotPositiveError: spec= param must be >=0

Additional info:
cmdline:        /usr/bin/python  /sbin/anaconda --liveinst --method=livecd:///dev/mapper/live-base
cmdline_file:   initrd=initrd0.img root=live:CDLABEL=Fedora-Live-Desktop-x86_64-20-1 rootfstype=auto ro rd.live.image quiet  rhgb rd.luks=0 rd.md=0 rd.dm=0  BOOT_IMAGE=vmlinuz0 
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         3.11.10-301.fc20.x86_64
other involved packages: python-blivet-0.23.9-1.fc20.noarch
product:        Fedora
release:        Fedora release 20 (Heisenbug)
type:           anaconda
version:        20