I had a problem with time machine that caused me to stop using it. When I switched (think it was under 10.5) from regular to filevault it stopped doing backups

I had a problem with time machine that caused me to stop using it. When I switched (think it was under 10.5) from regular to filevault it stopped doing backups. I happened to pay attention to the time that it took and noticed it seemed extremely quick. I decided (as I mentioned in another reply here) to use Super Duper which makes a clone of your hard drive and is easy to verify (just boot from the cloned drive).