Using advice on the Internet, and trying to install a new distribution, I had to make an entry on the USB flash drive through the unpacking of an iso-image.
Again, it did not work. I decided to overwrite through the interface, having previously cleaned the flash drive.
And then there was a problem because the file manager and the program can not delete the contents, perhaps because the folders themselves are locked up and require root .
How to solve this problem?
Distribution - Xubuntu
. Put - Linux Mint LXDE
(correct)