Hi, I think i have created a working cron that syncs two hard drives weekly.
if i do
sudo /etc/cron.weekly/backup_HDD1
the sync is started.
Now that’s how it is when the files are copied, I think it ends with an error.
rsync: [receiver] chown “/mnt/…………..Backup/………./………./xyz.xyz” failed: Operation not permitted (1)
However, the files end up on the hard drive.
My question: is that correct? 
And how can I check whether the cron is really running Monday at 3 a.m.?
This usually happens when the permissions on the destination don’t match. To test this, it’s best to run the command as root rather than as a regular user. It can also occur if the file system format on the destination doesn’t support Unix permissions, for example NTFS or FAT.
Just check via journalctl or add a log to the script.
sent 301,20G bytes received 323,39K bytes 84,88M bytes/sec
total size is 301,13G speedup is 1,00
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1338) [sender=3.4.1]
[Di 31. Mär 23:36:33 CEST 2026] 
Backup mit Fehlern beendet!
[Di 31. Mär 23:36:33 CEST 2026] === Backup-Skript beendet ===
The error was due to the exFAT formatted hard drive.
Just add to the rsync line --no-owner --no-group
That’s what I told you
Anyway this will make your backup useless and can probably not be used to restore anything if needed.