So, I tried to update the cache, First I tried to find the icons of LAN Messenger:
[[email protected] ~]$ find /usr/share/icons/* -regex '.*?lmc.*?'
Then I run the command you suggested (w/sudo privileges and --force option):
sudo gtk-update-icon-cache -f /usr/share/icons/hicolor
This actually update “icon-theme.cache”, but this not solve missing icon. I investigate on other icons type that are resident in notify, and I discovered that is of Scalable Vector Graphics (".svg") types… Perhaps this could be the reason? LAN Messenger has only “.png” icons type…
However the issue of the missing sound, I did not find anything about it on the internet. The only question that comes to me is that my notebook has 2 audio outputs and perhaps LAN messenger fails to recognize the main audio card … I don’t know …