Windows 7: Copied files from one HDD to another, and some files are now bad.

I wasn't sure whether to put this in a hardware section, as I suspect the problem is either memory or an HDD, but I thought I'd start with the general section.

The short story:
I am using Adobe Lightroom to view and edit my photos. I noticed errors on a few of the photos (something like 'error reading file' or 'end of file error'. The files are RAW picture files, in the .NEF format (from a Nikon). Lightroom is never supposed to edit these files (to do editing it uses a sidecar with XML in), so the problem shouldn't be due to Lightroom.

I have copied a bad file onto a laptop, and the file is indeed bad (you can load and see the photograph, but can't edit or save it). The files got onto my HDD when I copied thousands from an old, smaller HDD. I still have the old HDD, and I have tested an original file, which is good (works as expected). I compared the original file with the bad file using a binary editor, and there were a few tiny differences. The bites were different at 4 addresses:
Address: 25EAF6A Contents file 1: CA file 2: C2
Address: 264AF6A Contents file 1: 39 file 2: 31
Address: 26BAF6A Contents file 1: 5E file 2: 56
Address: 27CAF6A Contents file 1: AA file 2: A2

So the addresses were very similar (all ending AF6A), and the data at those addresses was all different by 8 (CA - 8 = C2, 39 - 8 = 31 etc).

My problem:
I copied thousands of these files, and I have no idea how many are bad (I have to try to edit them to check). I have no idea what caused the problem, whether it's a bad new HDD, or whether there was a problem with the memory while I was doing the copy.

Prior to doing the copy, I installed the new HDD, and installed extra memory at the same time (I had 6GB triple channel, and added 12GB - same manufacturer, same voltage, same timings). I started getting BSODs after the install, about once a day, and put that down to the memory (I ran memtest which passed), but I think I may also have a problem with my SSD (used for the OS), which I've just taken out. I'm having lots of problems, which I'm finding hard to solve, but...

the main thing I want to find out is what caused these files to get corrupted (I'm a photographer, so the files are my job) - is it likely to be the memory, or HDD, and are there any tests I can perform on the HDD to see if it has a problem?

Many thanks for any advice, I'm in quite a pickle.

If you have the original good copy, you might try reformatting the drive with the faulty files and attempt to reload them. If the files are still corrupt then try a different recipient drive such as a portable USB drive. Adding ram is unlikely to be a factor, but you could take out the extra ram just for peace of mind.

Thanks for the reply.

I'm actually thinking it's the memory that was in error. I'm thinking that the fault didn't occur when I copied the files from the old drive to the new drive, I think the error happened this week. I removed the files from Lightroom (not removing them from the disk, so they were untouched), renamed the files (as they were incorrectly named) and re-imported them into Lightroom. While Lightroom should never change the files, it can move them when you import them, and I believe that a memory error while it did this has caused the problem.

I've already taken the ram out, and brought replacement files over, which are fine.

If my assumptions are correct, I won't have any other bad files, so I'll need to spend some time checking that.

If the files are important you should make more than one independent backup copy

I do take more than one copy, but I do it when I feel like it, rather than as part of a well planned backup routine. There are several types of files I care about (photos, music, documents etc), all in different folders on different drives - I should find out an automated way of backing them up regularly.

Shame your ram didn't work, it would be worthwhile checking out your motherboard manufacturers website for any clues on ram amount and compatibility. The other way to speed up your system is an SSD with Windows and programs which you use frequently on one partition. The Samsung 840 PRO series are very fast.

Maybe robocopy is a possible solution fro you?
ROBOCOPY - Create Backup Script

It was the right stuff, I just think it was faulty. See what the retailer says when they test it.

I've had an SSD for the last 2 years, but along with my RAM problem, that's been playing up. It was stable until I put the RAM in, and then last week everything went pear-shaped. Sometimes when I'd boot my Bios could see the SSD, sometimes it couldn't (note, the corrupt files I had were not on the SSD, and my problems first started when I put the RAM in 2 months ago, and the Bios could still see the SSD). I created a drive image, and put that onto another HDD, and everything's been stable since. I had my page file on the SSD, so I don't know if the regular file writing caused the SSD issues?
Thanks. If I need to replace my SSD, I'd been looking at the Samsungs - I was looking at the basic and evo versions.

Looks perfect, thank you.

If you find the command line option too tricky, there is also SyncToy.

SyncToy - Backup User Data

I'm an old DOS user, so I like command lines, and just a brief look at the link above makes me think it's perfect for me.

I have no excuse for not sorting out a backup routine years ago.