A number of people are reporting issues (massive backups, backups hanging, etc), and I think the root of all of these problems may be that BackUpWordPress is no longer excluding the backup directory from backups.
I've seen two causes for this:
In most of the cases, the backup directory is simply no longer being automatically excluded from backups, and without that exclusion all of the old backups are being included with each new backup.
But in one case the problem was that the default location where backups were being stored inexplicably changed from:
…and since there was no exclusion for the old backup directory, all of the old backups were being included with each new backup.