unity8-dash crashed with SIGSEGV in mir_buffer_stream_get_egl_native_window()

[sanjay]

unity 8 has lost its system settings,since I deleted /usr/bin/system-settings for removing unity8 and reinstalling as per some blog.
How can I make a clean install for unity8 mir

ProblemType: Crash
DistroRelease: Ubuntu 16.10
Package: unity8 8.14+16.10.20160922-0ubuntu2
ProcVersionSignature: Ubuntu 4.8.0-17.19-generic 4.8.0-rc7
Uname: Linux 4.8.0-17-generic x86_64
ApportVersion: 2.20.3-0ubuntu7
Architecture: amd64
Date: Wed Oct 5 21:13:00 2016
ExecutablePath: /usr/bin/unity8-dash
ProcCmdline: unity8-dash --desktop_file_hint=/usr/share/applications/unity8-dash.desktop
ProcEnviron:
 LANGUAGE=en_IN:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
 SHELL=/bin/bash
SegvAnalysis:
 Segfault happened at: 0x7f26b88afdd6 <mir_buffer_stream_get_egl_native_window+22>: mov (%rdi),%rax
 PC (0x7f26b88afdd6) ok
 source "(%rdi)" (0x00000000) not located in a known VMA region (needed readable region)!
 destination "%rax" ok
SegvReason: reading NULL VMA
Signal: 11
SourcePackage: unity8
StacktraceTop:
 mir_buffer_stream_get_egl_native_window () from /usr/lib/x86_64-linux-gnu/libmirclient.so.9
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqpa-ubuntumirclient.so
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqpa-ubuntumirclient.so
 ?? () from /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/libqpa-ubuntumirclient.so
 QWindowPrivate::create(bool) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
Title: unity8-dash crashed with SIGSEGV in mir_buffer_stream_get_egl_native_window()
UpgradeStatus: Upgraded to yakkety on 2016-10-04 (0 days ago)
UserGroups: adm cdrom dip libvirtd lpadmin plugdev sambashare sudo

[Apport retracing service (apport)]

StacktraceTop:
 mir_buffer_stream_get_egl_native_window (buffer_stream=0x0) at ./src/client/mir_buffer_stream_api.cpp:158
 nativeWindowFor (surf=<optimized out>) at ../../../src/ubuntumirclient/window.cpp:70
 UbuntuSurface::UbuntuSurface (this=0x5581de026310, platformWindow=0x5581de0262a0, display=<optimized out>, input=0x5581ddb39d10, connection=<optimized out>) at ../../../src/ubuntumirclient/window.cpp:338
 UbuntuWindow::UbuntuWindow (this=0x5581de0262a0, w=0x5581ddc47e50, input=0x5581ddb39d10, native=<optimized out>, eglDisplay=0x5581dd8be250, mirConnection=0x5581dd8bcad0) at ../../../src/ubuntumirclient/window.cpp:611
 UbuntuClientIntegration::createPlatformWindow (this=0x5581dd842bc0, window=0x5581ddc47e50) at ../../../src/ubuntumirclient/integration.cpp:214