cgsecurity.org

Windows volume management displays my external HDD as RAW and refuses to read it.
Diskpart displays my drive's partition type as RAW and doesn't want anything to do with it.
Chkdsk says it sees an NTFS system and offers to fix bad indexing in file entry 5, but - as that's the root folder in NTFS - I didn't let it. Just in case. Yet.
Testdisk says the MBR is fine, extrapolated would be the same, copies match, NTFS system is readable, and let me copy all the files off. Good.
(I wish Testdisk kept a log of files copied or marked for copying, so that I could continue where I left off if the drive happens to have a wonky USB connector, or wonky USB-to-SATA interface, or wonky SOMETHING that causes it to intermittently disconnect. But never mind me.)
So, aside from reformatting the drive (which I now could do, I guess), and letting Chkdsk have a go - how do I try to actually fix it, if my MBR is fine (and I checked - it's not bootable, so it's all zeroes except for a serial number and a perfectly fine, single partition table entry)?

As you have copied your files, you should try the "chkdsk /f".
No idea about the origin of the problem, it may also be some bad sectors.

I did, eventually, try chkdsk and indeed it fixed the drive without a hitch. I wonder, therefore, if that wasn't a case of Windows protecting the filesystem from damage, although it would've been nicer on its part if it mounted it in read-only mode. I guess that's a "case closed", with big thanks to Testdisk for being able to copy my data off.

My only wish is that Testdisk could either log files successfully (or onsuccessfully) copied, or perhaps have an option to skip existing/same-sized files on copy. That would make emergency data copying safer.

Cheers!