How to fixed icon (lxqt) are missing after upgrade lubuntu

After I upgrade lubuntu from 22.04 to 24.10. The icon (lqxt) are missing on some page such as Desktop / File Manager / lxqt perference as image

Solution

1. Update OS First!

sudo apt update
sudo apt upgrade

2. Reinstall lxqt

sudo apt install --reinstall lxqt-core lxqt-panel lxqt-config lxqt-session
sudo apt install --reinstall lxqt-theme-* lxqt-qtplugin
sudo apt install --reinstall adwaita-icon-theme hicolor-icon-theme

3. Clear icon

rm -rf ~/.cache/icon-cache.kcache
rm -rf ~/.cache/thumbnails/*

4. reapply theme setting in LXQt Configuration Center > Appearance > Icon Tab
   choose a different icon theme

5. Log Out and Log In again / or try to restart
6. Problem solve