Once I looked for size of one folder on that HDD and Windows showed 0 Bytes, I have reconnected HDD and after that I could no longer access my files. I have found that I am not the only one who faced with this problem, for example here.
HDD: GPT, NTFS, 1 big partition; it was filled up to about 2-2.2TB, mainly with large (10-30GB) files. No OS was installed on it.
System: Win7, 64bit.
When I connect HDD, Windows asks me to format it. Of course, I don't do it.

Windows recognizes it as 3TB unformatted drive.

I was hoping that R-Studio will help me out. But it found only the last few copied files. All the other files (notice that it found more than 10 mil of files; the max number of files that could be in HDD is around 1000) were wrongly identified.

S.M.A.R.T. shows no problems. LifeGuard (WD utility for HDDs) as well.

When I connect HDD via eSata TestDisk sees only 800GB.

But when I connect it via USB 3.0 TestDisk sees 3TB.

And here are some other print screen of TestDisk.



Quick Search is very slow. It takes 1 second to analyze 1 segment, in other words it will take over 4 days to analyse this HDD. And yes, I run TestDisk as administrator.
So, what should I do next? Please help!