Sorry, I don't know how to recreate the issue. What I do know:

• I had one local uncommitted change in the repository I was looking at.
• The view looked strange:
  • The staged and unstaged file views were empty (I hadn't staged the change yet).
  • The checkbox next to staged file view was ticked, the one next to the unstaged view was unticked.
• I tried to check the unstaged files checkbox, but nothing happened.
• Then I tried unchecking the staged files checkbox, and SourceTree crashed with below stack trace in the log

2015-02-10T18:00:08: Stack trace:
at System.Linq.Enumerable.Select[TSource,TResult](IEnumerable`1 source, Func`2 selector)
at SourceTree.ViewModel.FileStatusViews.AbstractSelectableFileListViewModel._UnstageAll() in c:\projects\atlassian.com\dev\bitbucket.org\sourcetreewin\ViewModel\FileStatusViews\AbstractSelectableFileListViewModel.cs:line 733
at System.Windows.Controls.Primitives.ButtonBase.OnClick()
at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
at System.Windows.Input.InputManager.ProcessStagingArea()
at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)