I have lost a lot of movies (Personal and downloaded) on my usb attacked drives. I have three attached 2 8tb and one 5 tb, 10tb data lost among a backup of my former 4tb nas so I am very disappointed with the version 5 of the OS.
how was the external disk drive formatted.
you can check files and directory with another computer.
I generally run a sector by sector test before connecting a backup disk drive to my NAS and rotate then every 3 to5 years.
The USB BACKUP app sync function will remove files on the backup external disk if you delete the files on the NAS. and there were some changes from the OS3 USB Backup app.
For use on my dl2100 nas i format external drives as exFat
The directories are just showing empty
Thank you for this answer. This might also be why the only external drive formatted in ntfs is shown in my cloud and on my mobil app.
USB backup app in OS5 also has some problems with exfat formatting. ( it can mess up reading of the creation time format )
only small reason to use exfat was for easy reading on a mac computer but there is software to handle that if needed