I back up my files like this:

attic create --stats $REPOSITORY::`hostname`-`date +%Y-%m-%dT%H-%M-%S` $BACKUP_DIRS $BACKUP_EXCLUDES >> $LOGFILE 2>&1 || {
    echo "Error executing attic create." >> $LOGFILE
    mail_report
    exit 1
}

Today I 've got the following error:

attic: <PATH>/temp/maven2-tmp2062034583962716927.dir/_d.fdx: [Errno 2] No such file or directory: '<PATH>/temp/maven2-tmp2062034583962716927.dir/_d.fdx'
...
attic: Exiting with failure status due to previous errors
Error executing attic create.

I presume the filesystem has changed between backup processing phases. Of course I can exclude <PATH>/temp but maybe the exception handling should be changed so that in this case the errors are logged as warnings but do not result in terminating attic with an error.