I, too, have used Retrospect for many years, and without any overwhelming problems. However, I find duplicating my main drive to an external drive both efficient in the long run and, shall we say, less stressful. First of all, my purpose in backing up my drive is to have everything available when disaster strikes. Why keep something on my drive that I don't need or don't want? Second, I simply select Duplicate and, a couple of clicks later, I take a lunch break or read a short story. Finally, if disaster does strike, I simply reverse the backup.
I have noticed about a half dozen or so minor error notations — but no error numbers — but these have never seemed to impede a reverse backup. Now that I have noticed the question about Spotlight, I shall look further into this — and perhaps let Dantz in on the secret as well.

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Just plain Bill