Some icons on my system are invisible I can see there names only. When I switched my account it works fine with another account but my main account encountered this issue
Which?
My guess would be the theme/icons on your default desktop don’t have icons included for the apps missing the graphics. But, of course that’s just a guess because you never gave us any info regarding the installed theme/icons in use or the programs missing the icons.
Perhaps delete/rebuild your icon cache? The method varies between Gtk & Qt, so do your research.
regards
Go to kde settings and select icons to beauty line and reboot.
It should solve the problem.
This happened to me when I selected a global theme which didn't have icon pack.
thanks problem solved
Go to LXqt apperance setting and select icons theme window. Deselect "colorize icons based on widget style (palette) " option . This could solve icon disappering problem in lxqt gaurda edition. Dark icons themes may not be visible in dark background..