# Cannot start Slicer on LInux - cannot connect to X server

**URL:** <https://discourse.slicer.org/t/cannot-start-slicer-on-linux-cannot-connect-to-x-server/18302>\
**Category:** Support\
**Created:** [June 23, 2021, 2:23pm UTC](https://discourse.slicer.org/t/cannot-start-slicer-on-linux-cannot-connect-to-x-server/18302 "2021-06-23T14:23:11Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Fabio\_Geraci](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fabio_geraci/32/11355_2.png) [@Fabio\_Geraci](https://discourse.slicer.org/u/Fabio_Geraci)\
**Post date:** [June 23, 2021, 2:23pm UTC](https://discourse.slicer.org/t/cannot-start-slicer-on-linux-cannot-connect-to-x-server/18302/1 "2021-06-23T14:23:11Z")

</div>

this is my output

```auto
~/Slicer-4.11.20210226-linux-amd64/Slicer
Slicer: cannot connect to X server 192.168.0.1
fec0:0:0:ffff::1
fec0:0:0:ffff::2:0

```

---

<div class="post-metadata">

**Author:** ![Fabio\_Geraci](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/fabio_geraci/32/11355_2.png) [@Fabio\_Geraci](https://discourse.slicer.org/u/Fabio_Geraci)\
**Post date:** [June 23, 2021, 7:44pm UTC](https://discourse.slicer.org/t/cannot-start-slicer-on-linux-cannot-connect-to-x-server/18302/2 "2021-06-23T19:44:24Z")

</div>

I am running a jupyter notebook, where slicer is invoked to show images, the very first tutorial. In my bashrc i have

```auto
#
export SITK_SHOW_COMMAND=${HOME}/Slicer-4.11.20210226-linux-amd64/Slicer
export PATH="$PATH:${HOME}/Slicer-4.11.20200930-linux-amd64"
# 
#export DISPLAY=localhost:1.0
#

```

an i run jupyter notebook from MobaXterm, with the following error:

```auto
QStandardPaths: XDG_RUNTIME_DIR not set, defaulting to '/tmp/runtime-fabiog'
Switch to module: "Welcome"
The X11 connection broke: I/O error (code 1)
Slicer: Fatal IO error: client killed
XIO: fatal IO error 0 (Success) on X server "localhost:10.0"
      after 1361 requests (1361 known processed) with 0 events remaining.
free(): invalid pointer

```

---

<div class="post-metadata">

**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [June 25, 2021, 2:05am UTC](https://discourse.slicer.org/t/cannot-start-slicer-on-linux-cannot-connect-to-x-server/18302/3 "2021-06-25T02:05:18Z")

</div>

The question was already posted here and turned out to be a configuration error on the user’s computer:

> <https://github.com/Slicer/Slicer/issues/5707>
>
> Good Morning,
> 
> My setup: Windows 10 - Ubuntu WSL1 (Welcome to Ubuntu 20.04.2 L…TS (GNU/Linux 4.4.0-19041-Microsoft x86\_64)) - MobaXterm
> 
> In bashrc I have the following lines:
> \`\`\`
> \#
> export SITK\_SHOW\_COMMAND=${HOME}/Slicer-4.11.20210226-linux-amd64/Slicer
> export PATH="$PATH:${HOME}/Slicer-4.11.20200930-linux-amd64"
> \#
> \`\`\`
> Issue: I am trying to launch 3D Slicer from MobaXterm, using:
> \`~/Slicer-4.11.20210226-linux-amd64/Slicer\`
> It seems to be working but then I get the following error:
> \`\`\`
> QStandardPaths: XDG\_RUNTIME\_DIR not set, defaulting to '/tmp/runtime-username'
> Switch to module: "Welcome"
> Slicer: Fatal IO error: client killed
> The X11 connection broke: I/O error (code 1)
> XIO: fatal IO error 0 (Success) on X server "localhost:10.0"
> after 1362 requests (1362 known processed) with 0 events remaining.
> free(): invalid size
> \`\`\`