Xubuntu Xenial Beta 2 live image is not able to start

[José Jorge]

Downloaded Xenial Daily from 2016-03-22 on Windows, created a live USB using "Linux Live USB creator" and tested on an Inspiron 14 3000 series laptop, system boots correctly, Xubuntu loading image (boot image) is displayed, but it seems to fail just before launching the ubiquity installer, because no language selector nor install/try Xubuntu options appear, instead, I get a window with following message:

Sorry, Ubuntu 16.04 has experienced an internal error.
If you notice further problems try restarting the computer.

If clicking on the "Show details" button I get this information:

ExecutablePath
  /usr/lib/ubiquity/bin/ubiquity
Package
  ubiquity 2.21.50
Problem Type
  Crash
Title
  ubiquity crashed with GLib.Error in customize_installer(): vte-pty-error: grantpt failed: Operation not permitted (1)
Traceback
  Traceback (most recent call last):
  File "/usr/lib/ubiquity/bin/ubiquity", line 649, in <module>
    main(oem_config)
  File "/usr/lib/ubiquity/bin/ubiquity", line 635, in main
    install(query=options.query)
  File "/usr/lib/ubiquity/bin/ubiquity", line 264, in install
    wizard = ui.Wizard(distro)
  File "/usr/lib/ubiquity/bin/ubiquity/frontend/gtk_ui.py", line 348, in __init__
    self.customize_installer()
  File "/usr/lib/ubiquity/bin/ubiquity/frontend/gtk_ui.py", line 912, in customize_installer
    self.vte.spawn_sync(0, None, tail_cmd, None, 0, None, None, None)
  GLib.GError: vte-pty-error: grantpt failed: Operation not permitted(1)
ApportVersion
  2.20-0ubuntu3
Architecture
  amd64
Casper
CasperVersion
  1.367
CrashCounter
  1
Date
  Tue Mar 22 18:31:25 2016
Dependencies
Distro Release
  Ubuntu 16.04
InstallCmdLine
  bootkbd=us console-supet/layoutcod=en:US console-setup/variantcode=nodeadkeys locale=us_s persistent noprompt cdrom-detect/try-usb=true file=/cdrom/preseed/cli.seed boot=casper initrd=/casper/initrd.lz splash -- mayby-ubiquity
InterpreterPath
  /usr/bin/python3.5
JournalErrors
LiveMediaBuild
  Xubuntu 16.04 LTS "Xenial Xerus" - Beta amd64 (20160322)
PackageArchitecture
  amd64
ProcCmdLine
  /usr/bin/python3 /usr/lib/ubiquity/bin/ubiquity --greeter --only
ProcEnviron
  Error: [Errno 13] Permission denied: '/proc/3717/environ'
ProcMaps
ProcStatus
ProcVersionSignature
  Ubuntu 4.4.0-15.31-generic 4.4.6
PythonArgs
  ['/usr/lib/ubiquity/bin/ubiquity', '--greeter', '--only']
SourcePackage
  ubiquity
Tags
  xenial ubiquity-2.21.50 cli
UbiquityDebug
UbiquityDm
UbiquitySyslog
Uname
  Linux 4.4.0-15-generic x86_64
UpgradeStatus
  No upgrade log present (probably fresh install)
UserGroups

I was unable to connect to the Internet so I couldn't send the report within the live USB environment, after trying and getting a connection error, a new window appears with this message:

The installer encountered an unrecoverable error. A desktop session will now be run so that you may investigate the problem or try installing again.

Clicking on the "OK" button on that window will bring a black window with some white text and then back to a "normal" live graphical session, with a link to "Install Xubuntu 16.04 LTS" on the desktop.

I'll try to add more information as I can gather it.

[José Jorge (mexchip)]

Seems a duplictae of https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1560459

sorry for not confirming before submitting the bug.