Created Unassigned: Could not load file or Assembly Xceed.Wpf.Toolkit.AeroLite [22543]

I am using WPF Extended toolkit (only DateTimePicker control.) I started receiving FileNotFoundException at some point in my application.

Could not load file or assembly 'Xceed.Wpf.Toolkit.AeroLite, Version=3.0.0.0, Culture=neutral, PublicKeyToken=3e4669d2f30244f4' or one of its dependencies. The system cannot find the file specified.

I was trying to clear build and start a new one, but binary output contains only following assemblies:

11.05.2017 10:55 415 744 Xceed.Wpf.AvalonDock.dll
11.05.2017 10:55 86 016 Xceed.Wpf.AvalonDock.Themes.Aero.dll
11.05.2017 10:55 78 848 Xceed.Wpf.AvalonDock.Themes.Metro.dll
11.05.2017 10:55 83 456 Xceed.Wpf.AvalonDock.Themes.VS2010.dll
11.05.2017 10:55 2 227 200 Xceed.Wpf.DataGrid.dll
11.05.2017 10:55 1 054 720 Xceed.Wpf.Toolkit.dll

Where can I find Xceed.Wpf.Toolkit.AeroLite assembly?