Unable to change folder icons

Hi all,

I am unable to change folders default icons into custom images. When I try the normal way with Nemo (properties -> click on the icon image) the properties window suddenly dissapears. I tried also unsuccessfully with Nautilus and Dolphin, even with admin privileges.

The point is that I had no problem until I installed a desktop theme, but reverting to the previous default theme does not solve the issue.

I use Ubuntu 19.10 Cinnamon (tried also using a "guest" account with basic packages - no success)

I'd appreciate any clue. Thanks,

don't know, but it has to do with theming. gtk2,gtk3, look into cinnamon themes on line, in the repo. look in your settings on appearance, theme, icons, etc.. anything that might have to do with icons and themes to change the look of folders and app windows.

https://cinnamon-spices.linuxmint.com/themes