Hi, I have exactly the same problem with this plugin then until the problem is resolve, I use another.
If you use WordFence try deactivating it and then backup then reactivate it. Works for me.
Thanks ipsodesign … this worked;-)
The solution mentioned above worked exceptionally well for a couple of my sites that were not backing up; but I still have a couple that have the exact same problem – and they don’t have Wordfence installed. I wondered if the Ithemes plugin was causing the same issue, but it still just hung forever even with that security plugin was disabled. This has been a great plugin for a good while for me, but there’s obviously something happening in how it “plays” with other plugins and I can’t afford to wait until – or if – all those issues are worked out. I’m probably moving my backup functions to another plugin. It’s been great for quite a while, but this is too important to go monkeying around deactivating plugins here and there trying to figure out why it won’t work.