output of ls

Which red box?

please post picture and elaborate more

"ls -l" is usually showing files, security properties and file size - so you are probably talking about file size  here... (but a screen shot or text output would help indeed...).

I think red on black is by default a symlink to a nonexistent file (an "Orphan"),
and black on red is a "SETUID" file (u+s).

See "/etc/DIR_COLORS" or run "dircolors -p" (red background = 41, red text = 31).

Sorry for missing the file. Tks
Centos.png

Tks