I come back last night to find that not only hadn't it finished, it hadn't even started!
The first thing it does prior to each backup is look at what files it needs to backup. It turns out that WINE's directory contains directories which are actually links to all of your hard drives and partitions, so that they can be presented to Windows programs as C:, D: etc etc. So what was happening is that the backup program was looking at everything, discovering these 'directories', looking at them, discovering that one of them - the one with my home partition - had these 'directories', looking at them, discovering that...
I'm not sure just how deep the recursion got before the program gave up because the path names to the files were too long, but the number of files it thought I had was enormous.
This entry was originally posted at http://lovingboth.dreamwidth.org/473818.html, because despite having a permanent account, I have had enough of LJ's current owners trying to be evil. Please comment there using OpenID - have and if you have an LJ account, you can use it for your OpenID account. Or just join Dreamwidth! It only took a couple of minutes to copy all my entries here to there.