Your NewBackupFilename contains ":" which is not a valid character in a filename in Windows.
You could do something like this: >>> NewBackupFilename = DirBackup + '\\' + '%s' % str(datetime.today()).replace(':', '-') + '.tar.bz2' >>> NewBackupFilename 'c:\\\\skpdc01\\\\Backups\\2005-01-21 12-26-21.373000.tar.bz2' >>> TarFileBackup = tarfile.open(NewBackupFilename, 'w:bz2') >>> # Works! I changed your DirBackup to 'C:\skpdc01\Backups' Thanks, --Kartic -- http://mail.python.org/mailman/listinfo/python-list