Almost 48 hours to consolidate so far

Since I've been using TruImage, consolidate has never worked. Twice before now I've had the backup run out of space (limit should be 200GB on a 500GB NAS). Looking at the log every consolidate failed with "network error", which then leaves behind the .tib file with the long (GUID) name, and ultimately runs out of space. On both those occasions I'd deleted the whole backup and started again.

This time round I've again got to the point the consolidate should kick in, but that was almost 2 days ago. And it's still running!

My original full backup was some 80GB, but some of the daily ones have only been 500KB. As I understand it it's merging the two oldest, so does that mean every single day it's going to read and write 80GB +? This doesn't seem like a very sensible way of organising things.

The output file is now up to some 55GB, but I'm sure 24 hours ago it was about the same size (but this morning it was smaller again). Plus 24 hours ago it was saying 20 hours left, now it's saying 1 day and 19 hours left! According to the log this is the same job, and all the numbered files are there - nothing has been deleted.

Even if it is reading and writing it should take this long, the original backup didn't.

Any suggestions? This very much seems to be the weakpoint in the whole system.