Unable to install Addons in Linux contaner: Webwindow is not valid. It was closed by user or the process was terminated.

I am running matlab using the official container images, with GUI access by forwarding the X11 socket.

When I try to install anadd-on using the "Get add-ons" menu item, I eventually get a backtrace:

```

Error using matlab.internal.cef.webwindow/errorOnInValidWindow

Webwindow is not valid. It was closed by user or the process was terminated.

Error in matlab.internal.cef.webwindow/bringToFront (line 673)

obj.errorOnInValidWindow()

Error in matlab.internal.webwindow/bringToFront (line 225)

bringToFront(obj.impl)

Error in matlab.internal.addons.AddOnsWindow/bringToFront (line 72)

obj.webwindow.bringToFront();

Error in matlab.internal.addons.Explorer/bringToFront (line 73)

obj.addOnsWindowInstance.bringToFront();

Error in matlab.internal.addons.launchers.showExplorer (line 138)

matlab.internal.addons.Explorer.getInstance.bringToFront;

```

The process is totally sporadic. Sometimes a blank window comes up and stays there, sometimes no window is shown at all, sometimes it comes up and minimises quickly, sometimes it flashes before getting the trace. And sometimes it does appear long enough for me to view a plugin, and after about fifty attempts, finally I was able to install the toolbox I needed. I see no logs output to stderr when running matlab, and no menu for getting debug information. Plenty of other threads have mentioned Windows AntiVirus software, but obviously this doesn't apply here, and if some process has died in the backgorund, I see no obvious way of finding out what has gone on except breaking out htop and watching for something to disappear, or resorting to strace.

I have tried using the web interface instead, but this does not allow me to open the Add-on window at all.

Answer 1

[Gowthami]

Hello Ben,

This may be related to a known issue where unexpected behaviour occurs when using the Add-On Explorer or Add-On Manager.

The issue is caused by anti-virus software incorrectly flagging the Window Manager in MATLAB.

I recommend you go through the workaround mentioned in the following MATLAB Answer to resolve your issue - https://www.mathworks.com/matlabcentral/answers/1874312-trend-micro-s-security-software-prevents-matlab-s-access-to-matlabwindow-exe-file-inhibiting-web

[Ben]

Thanks for your answer! However as mentioned, I am running both on linux and inside a container. There's definitely no antivirus installed, I think the above link would apply only to a Windows system.

Answer 2

[Gowthami]

Hello Ben,

I understand that you are unable to install Add-Ons in Linux and getting an error as "Webwindow is not valid. It was closed by user or the process was terminated."

I recommend you check the following three points:

1. In MATLAB, go to "Preferences -> MATLAB -> Web" and see if "Use a proxy server to connect to the internet" is checked. If it is, un-check this option and see if the issue is still reproduced.
2. Make sure that any AntiVirus or Firewalls installed on the system are not blocking anything in the MATLAB installation directory.
3. Please disable any VPN before starting MATLAB. You can resume the VPN once MATLAB opens up.

[Ben]

Thanks, so:

1. Proxying isn't enabled, this is not checked
2. No AV is installed
3. Also not using a VPN.

I eventually managed to get to dmesg output and saw a segfault from the container I think, will have to look ito that later some time and post where it's originating from.