Got pointed to this tool SyncToy from Microsoft the other day and its is terrific for ensuring that all the files are copied onto drives. Its free and can be used to copy just the modified files from a working directory to external drives or other machines.

I have used it for a week and cannot fault it - saved me a load of time.

Find the overview here.

Did I mention it was free? Well it is free.

Roger

http://www.microsoft.com/downloads/details.aspx?FamilyId=49818CF1-2287-40EA-8A6F-57BD8695F23D&displaylang=en

Roger, thanks for the heads up on what sounds to be a good useful piece of software. I have a Western digital External drive that has software included that gives me the option of only backing up files that have changed or been added since the last (Sync) but maybe the microsoft has a better interface. I will give it a look.

Yes, neat toy.
Really good for synchronising offline (PC) and online (NAS) folders.

But it really gets upset when faced with 400000 images in a few hundred folders.
I'm trying to find a duplicate remover.
But haven't found anything that works yet.
I may have to write one.

wombat,

Try iView. The demo will find dupes by name and content.