unity8-dash crashed with SIGABRT in QMessageLogger::fatal()

I can not log in to Unity8 session on Ubuntu 16.04. When I try to log in to Unity8 session, only a black screen is shown. And when I return to Unity7 session, I get a crash report from apport.

To get to the default (unity7) session:
1- CTRL+ALT+F1
2- Log in
3- sudo systemctrl restart lightdm

ProblemType: Crash
DistroRelease: Ubuntu 16.04
Package: unity8 8.11+16.04.20160310.4-0ubuntu1
ProcVersionSignature: Ubuntu 4.4.0-12.28-generic 4.4.4
Uname: Linux 4.4.0-12-generic x86_64
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
Date: Sat Mar 12 19:17:22 2016
ExecutablePath: /usr/bin/unity8-dash
InstallationDate: Installed on 2016-01-16 (56 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160116)
ProcCmdline: unity8-dash --desktop_file_hint=/usr/share/applications/unity8-dash.desktop
Signal: 6
SourcePackage: unity8
StacktraceTop:
 QMessageLogger::fatal(char const*, ...) const () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
 ?? () 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
 QPlatformIntegrationFactory::create(QString const&, QStringList const&, int&, char**, QString const&) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
 QGuiApplicationPrivate::createPlatformIntegration() () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
Title: unity8-dash crashed with SIGABRT in QMessageLogger::fatal()
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo