Empty backup with innobackupex

I’m trying to create a full backup of my mysql database. It’s made of a mix of Innodb and Myisam tables.
When I run the command:
innobackupex --user=bkpuser --password=‘pwd’ /tmp/BACKUP/
the program does his thing and creates the timestamped directory.
It ends with “innobackupex: completed OK!”
But inside there are only empty directories and the ib_logfile and ibdata files.

When I try to restore it, it obviously generates empty databases.

What could cause this behaviour? I found no similar questions anywhere!

Thank you.

How are you restoring the backup? Can you provide the full backup log when you ran the innobackupex command? We will need more details.