Comment 10 for bug 703142

I'm getting the same problem:

If I delete the backup folder or change the backup destination folder it works for a few days then comes this error...

I have the same configuration on a Fedora system, also the same duplicity version and has been working without fail for some months now....

NAME="Ubuntu"
VERSION="13.04, Raring Ringtail"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 13.04"
VERSION_ID="13.04"

~ $ duplicity -V
duplicity 0.6.21

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1411, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1404, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1286, in main
    globals.archive_dir).set_values()
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 704, in set_values
    backup_chains)
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 717, in set_matched_chain_pair
    sig_chains = sig_chains and self.get_sorted_chains(sig_chains)
  File "/usr/lib/python2.7/dist-packages/duplicity/collections.py", line 930, in get_sorted_chains
    assert len(chain_list) == 2
AssertionError