I'm starting backup from the 'Settings' app, clicking the 'Back Up Now...' button. It seems to back up fine, but when it get to 'verifying backup...' the error message shows up:
Could not restore ‘~/.cache/deja-dup/metadata’: File not found in backup
It's a fresh backup, only one single directory.
~/.cache/deja-dup is symlinked to a folder on a extra hard drive (/dev/sdb1, ext3) mounted in /media/WD1TB.