This drive is kicking my butt.

[Wiley1]

[LaCie Porche Design, USB 3.0, external case with external power supply, more than 9 years old]

An end user brought this drive to me because it was throwing errors when she tried to read most files.
The first thing I did was pull the 2 TB Seagate drive out of the external case and connect it as a 4th SATA drive in one of my bench PC's.
Sometimes it is not even seen by Windows 10, but after connecting and disconnecting several times, it will appear in Disk Management and Windows.
The first partition is FAT32, 280 GB, labeled "LaCie Share". This partition passes all tests and all the files are accessible.
The remaining partition is FAT32, 1584 GB, labeled "Data".
The first time I ran SeaTools, the self-test failed at 56%.
Using Roadkil Unstoppable File Copy, I was able to salvage 900 files from one folder but 150 files were unreadable
Then, somehow, my test machine spontaneously rebooted overnight and I believe Windows 10 tried to fix the drive automatically.
Now, Disk Management can still see both partitions, and the LaCie partition is still good,
but all attempts to access the Data partition in Windows return "request failed due to fatal device hardware error"
SeaTools 5.0 can't even see the drive. SeaTools 1.4 sees it as "Unknown" and it passes both Short and Long Generic tests.

I'm pretty sure this drive now has at least three issues:
1) unreadable sectors, 2) intermittent SATA interface, 3) corruption introduced by a Windows failed repair attempt

What are my best next steps to try to recover more data from this drive?

[fzabkar]

[LaCie Porche Design]

Lipstick on a pig.

I'm pretty sure this drive now has at least three issues:
1) unreadable sectors, 2) intermittent SATA interface, 3) corruption introduced by a Windows failed repair attempt

What are my best next steps to try to recover more data from this drive?

You should have cloned the drive with HDDSuperclone or ddrescue. Now it's too late. Everything you did just tortured the drive until it died. :-(

[lcoughey]

Good thing the data wasn't worth much to the end user because it will cost a lot more for a pro now.

[Wiley1]

[LaCie Porche Design]

You should have cloned the drive with HDDSuperclone or ddrescue. Now it's too late. Everything you did just tortured the drive until it died.

Perhaps you are right, but..
I did consider cloning the drive, but a 2 TB target drive was not immediately available. And, this drive was less than 5% utilized.
I made a judgement that attempting to access readable data, folder by folder, would put less stress on the drive than trying to read 1.9 TB of never-used and non-relevant sectors.
My plan was working nicely until Windows came along and messed things up.

I'm not ready to agree with your statement that "it is too late now".
A botched software fix does not necessarily result in a hardware problem, and the drive has definitely not "died".
Keep in mind that the first partition is working perfectly for as long as the drive will stay online. And, the drive still passes the Short Generic test in SeaTools.
That proves that the hardware is good, at least in one section of the drive.
If the second partition was damaged by software, then there should be a software fix to recover it.

Can anybody suggest a tool that might repair the Data partition under these conditions?

[northwind]

Lipstick on a pig.

[labtech]

Since the second partition is the one used mostly by the end user, then that area would have developed bad sectors.
Cannot fix that.

To recover the files, cloning (or imaging to a file) is the best course of action. Suggested tools in earlier posts for best basic cloning are recommended.

You could still follow all these steps and using good data recovery software may yield success. However, it really depends on whether the file system's condition is still sound.

Or, of course, you could always refer the job to a data recovery specialist and collect a referral commission.
Here is one nearby you: https://prodatarecover.com/