This...is probably the biggest fuckup I have ever made with dd.
Basically, on a PC I was cloning, it didn't have any other HDDs, so I cloned each partition into its own disk image on a secondary partition. I would have done the whole disk had I had another disk handy, but I didn't want to be making an image of the image-in-progress and create an infinite loop.
So, on my main PC, I was working on merging the partitions into one VDI file, when I realized I probably fucked up my Windows partition, big time.
I had slimmed the Windows install down to ~35 GB before this, made a 40 GB VDI file in VirtualBox, and done something to the effect of "dd if=/dev/sda2 of=/dev/sdb".
The reason I am super concerned now is because I didn't even think of defragmenting before doing this, much less resizing the NTFS partition. I believe I have likely lost some of the files once on that disk because dd does not tell you if it fills up the target volume and has to stop, so anything beyond the 35 GB (including the NTFS end of partition data) is gone.
I have already reinstalled Windows on that box, so creating a new image is out of the question.
When I cloned the 531 GB partition (on the 40 GB volume, mind you), I could not mount the partition.
My question is: what should I expect to have to do to fix the NTFS volume, and what tools/guides do you guys recommend? I can't seem to find anything on Google related to a fuckup this big.
Any help would be extremely appreciated.
Edit: going to flag down @wendell, hopefully he can help.