Recently I had to send my UX32VD notebook back to ASUS for repairs under warranty (which turned out to be a completely painless experience, thankfully). Before I did, I made an image of the HDD to an external USB drive using Windows 7's backup tools. In the end the precaution was unneeded, but I decided keeping the image around might prove useful in the future so, instead of deleting it, I tried copying it to a more permanent location on my server. That's when I ran into trouble.
When Windows 7 makes a backup image, it actually generates several files containing system and partition metadata, more if you happen to have a couple of drives. These smaller files copied without issue -- it was the main drive image, a 80GB virtual hard disk (VHD), that managed to transfer around 8GB of itself before the OS threw an error.
I should mentioned at this time that the USB HDD is less than a year old and has spent 95 per cent of its operational life sitting on top of a PC case, so the corruption was not at all expected.
A scan using Windows' own "chkdsk" utility determined several issues with the file system, which I gave the OK to repair. Unfortunately, that didn't solve the problem, with the copy operation again dying at the 8GB mark. So, I turned to the internet for help.
Typing "data recovery" into Google gave me results for professional services that extract information from damaged drives and "undelete" utilities -- neither of which I was looking for (well, not the former just yet). After attempting various word combinations, "copy corrupted file" coughed up more relevant links. Unsurprisingly, I ran into plenty of paid-for products until I discovered the free "Roadkil's Unstoppable Copier".
(Just to be clear, I was more than willing to use something commercial, but I wanted to expend all cashless paths first.)
I downloaded the program and fired it up. I had a quick look at the options and spotted a slider that allowed me to set the tool's focus to "Best Data Recovery" or "Fastest Data Recovery". I went with the first choice, though in hindsight setting it towards the second a few notches might have been the better way to go.
This all happened on July 13. The screenshot above is the process it's made since then. To the right you'll find a cropped image of Process Explorer showing the process' start time (blurred for privacy).
Yes, it's still going after 23 days.
The reason for this is that the Unstoppable Copier tries to copy bad data many, many times, in the hopes that it'll extract a few extra bytes that the last attempt didn't get. As I mentioned, I probably could have been less conservative and chosen a faster setting, but I wasn't aware just how much slower the process would be on maximum.
A few times I've been tempted just to abort the recovery and forget the whole matter, but curiousity got the better of me -- will it ever manage the copy? Will the image even be usable? Seeing as I was able to access the image using VHD exploring tools before I started the copy, it should be OK, but your guess is as good as mine at this stage.
In two weeks' time, I'll be travelling overseas for just over a month. If I come back and it's still slaving away, I'll call it a day.
Whatever happens, I'll be sure to provide an update.