How do I login with NX / NoMachine? My attempts fail.

There are several situations which may occur and which can cause failure to log in via NX:

Screen stuck on 'Creating a new GNOME virtual desktop'

How do I log in with two-factor authentication

Password needs to be changed

Account over quota

Dbus errors (often introduced by local conda / anaconda / miniconda install in home directory)

A green screen is seen when logging in

A corrupted previous NX / NoMachine session


Screen stuck on 'Creating a new GNOME virtual desktop'

If you see this error it can be a symptom of several different issues. Please work through the list below, even if you do not see the specific error message quoted. If none of these solutions allow you to log in to HPC via NoMachine again, contact the Service Desk and mention that you have worked through all the items in this FAQ.

How do I log in with two-factor authentication

When logging in using NoMachine you enter your username and password and are then prompted for your two-factor Authentication code.

Password needs to be changed

If your password is approaching the time at which you must change it to comply with the 90 day password policy then you will not be able to log in with NX until you change your password. You can log in via SSH when you will see a message warning you that you will need to change your password soon - you can then change your password with the 'passwd' command. Alternatively, you can change your password via a managed Windows Desktop or Outlook web access.

Account over quota

Usually a failure to log in with NX is due to your account having gone over quota. The NX server session on SPECTRE stores some state files within your home directory; if you have reached or exceeded your  file quota, these cannot be created and NX fails.

If this happens it is still possible to log in via SSH (e.g. with PuTTY - to ALICE, to SPECTRE). Log in, check your quota with the command

quotacheck 

and if necessary delete any unwanted files (using the rm command), or move them to your scratch directory (using the mv command). Once some space has been cleared, it will be possible to log in with NX again.

You can see which files or directories in your home directory are using the most space with the command

homeusage

Dbus errors (often introduced by local conda / anaconda / miniconda install in home directory)

If you see an error message saying something like "Could not connect to session bus: Failed to connect to socket /tmp/dbus-jWUMQLCUP1: Connection refused":

NX dbus failure

Check that you have not added something to $PATH or $LD_LIBRARY_PATH in your ~/.bashrc or ~/.profile files which may have caused problems, eg:

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$HOME/splash/giza/lib
or:
export PATH="${PATH}:${HOME}/glimmer3.02/bin"
or, added automatically by running an installation script, eg:
# added by Miniconda2 installer
export PATH="$HOME/miniconda2/bin:$PATH"

or:

# added by Anaconda3 2018.12 installer
# >>> conda init >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$(CONDA_REPORT_ERRORS=false '/home/a/abc1/anaconda3/bin/conda' shell.bash hook 2> /dev/null)"
if [ $? -eq 0 ]; then
    \eval "$__conda_setup"
else
    if [ -f "/home/a/abc1/anaconda3/etc/profile.d/conda.sh" ]; then
        . "/home/a/abc1/anaconda3/etc/profile.d/conda.sh"
        CONDA_CHANGEPS1=false conda activate base
    else
        \export PATH="/home/a/abc1/anaconda3/bin:$PATH"
    fi
fi
#unset __conda_setup
# <<< conda init <<<

As you cannot log in via NX, you will need to log in via SSH and use a command line terminal to comment out the recent changes in ~/.bashrc or ~/.profile

To continue using NX with the convenience of the conda or other shell commands being available, copy the lines from ~/.bashrc instead to ~/.bash_profile

A green screen is seen when logging in

Sometimes, when resuming a suspended NX session (particularly from a different computer with a different monitor size or resolution), a green screen will be seen rather than the expected desktop session. See here for more information and how to fix this.

A corrupted previous NX / NoMachine session

If a previous session did not shut down or disconnect properly there may be invalid saved session data which is preventing access. If you have tried all of the methods above, log on via SSH (e.g. with PuTTY - to ALICE, to SPECTRE), then on the command line enter:

mv ~/.nx ~/.nx.bak

 

 

If you are still unable to log on to your desktop, please contact the Service Desk and mention that you have worked through all the items in this FAQ.

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