GTK version problems when starting KNIME from Ubuntu 16.04

Hi guys,

I’m trying starting KNIME from Ubuntu 16.04 and I have the following error message:

“Detected GTK version 3.18.9 which is know to cause screen artifacts. Read the F.A.Q. for more information (and how to suppress this warning)”.

In the mentioned F.A.Q. there are 2 possibilities to solve the issue:

You can run the KNIME application using older GTK 2 libraries by either exporting an environment variable before starting KNIME:

$ export SWT_GTK3=0
$ /opt/knime_server_4.3/knime

Alternatively, you can add a parameter to the knime.ini file that is located in the KNIME installation folder, such as (new lines in bold):


The first solution seems to works but the second it does not. This force KNIME to be launched every time from the command line preceded by the command “export SWT_GTK3=0”.

Why the solution of modifying the knime.ini file does not work? Does anybody has a clue for it?

Thanks in advance,


The second solution certainly works for me. Did you add the --launcher.GTK_version 2 on two different lines and before the -vmargs?

Hello Thor,

Thank you for your prompt reply. I just realized something odd. If I launch KNIME from terminal (with the knime.ini file modified as suggested in the F.A.Q.) the problem effectively does not appear anymore. Nevertheless when I launch KNIME from the dock (i.e. the Ubuntu-Unity left sidebar) the problem persist.

This is not a serious problem anyway it is strange.

Hi everybody,

I am experiencing a similar problem since yesterday. 

I installed KNIME version 3.4.2 on my linux machine running Ubuntu 17.10 (beta version) last December before Christmas. It was working fine until yesterday when, after some updates for Ubuntu were installed, it stopped working.

Several errors messages are thrown on the shell reading like:

(KNIME:6535): GLib-CRITICAL **: g_base64_encode_step:assertion 'in != NULL' failed

(KNIME:6535): Gdk-WARNING **: Couldn't map window 0x7f7d5339a020 as subsurface because its parent is not mapped.

(KNIME:6535): Gtk-WARNING **: Negative content height -3 (allocation 1, extents 2x2) while allocating gadget (node toolbar, owner GtkToolbar)

and so on...

Do you know what's going on?

Any idea is very welcome.



Kepa K.