I've been using various editions of Norton Ghost on XP and Vista for many years. Recently NG 14 has developed intermittent failures whilst trying to take incremental backups. Either the incremental has been the same size as the base, within a few percent, or the incremental process has taken so long, several hours rather than the usual few minutes, that I have given up.
I tried reinstalling NG 14, no improvement.
After tearing out my hair, I evenyually came upon this forum. Reading through, I have come to the conclusion that for some reason or other, probably MS Update, my C drive is now being defragmented on a regular basis.
My plan, that I have implemented today, is to schedule the defrag to run after the final incremental of the month and before the next month's base.
I'll send an update in January, to let you know if my plan has succeeded.