NullReferenceException: Object reference not set to an instance of an object UnityEditor.PreferencesWindow.ShowPreferencesWindow ()

i’ve have a problem.

i cannot open Unity>Edit>Preference windows

When i click that menu, The error occured like that
'NullReferenceException: Object reference not set to an instance of an object UnityEditor.PreferencesWindow.ShowPreferencesWindow () (at C:/BuildAgent/work/d63dfc6385190b60/Editor/Mono/PreferencesWindow/PreferencesWindow.cs:145)

uninstall and install twice.

but this issue is not resolved.

how can i fix this problem?

Both of you report the bug:
http://unity3d.com/BugReportingFAQ