rayjoh wrote: Unmount /media/backup and check if the files was hidden by the mounted disk.

Thanks ! The files were in /media/ after unmounting the HDD

Hello, I have the very known problem of full SD card. The file system is expended. The RPI is used as a backup server. The connected usb HDD has certainly failed during a backup, so data was saved on the SD card. At least it's what I heard on the forum. But where are those files so I can remove them...