Short answer: There is nothing you can sensibly do in your current situation, except stop trying to use the drive, and protect it until you're in a position to send it to a pro (though choose your pro carefully, preferably based on a recommendation - one of the bigger names is generally
not recommended, for example). This is based on your comments about how much you want the data back. More risky DIY recovery attempts (though still requiring additional h/w), are
possible but could make any later pro recovery either more expensive / difficult or even impossible.
Further comments:
AusAbe wrote:
However, the "Toshiba Mass Storage" device appears in the "Disk Management" only after it has been connected for some time. When it does it appears, it's unrecognized, not initialized and doesn't have a partition; although approximately 900GB are saved on it. So, I can't assign a letter to the drive or apply any of the remedies I've read.
I don't know what "remedies" you're thinking of, but none of them should include making changes to your current disk!
AusAbe wrote:
Obviously, I don't want to lose the 900GB of info so haven't initialized or formatted it. I tried to create a small 8MB partition, but received the "cyclical redundancy check" error.
Do
NOT try making a new partition (or formatting the disk, or indeed any other writing to the disk). Your problem, as confirmed by the CRC error, is not a "lost partition" or whatever vague wording you might find used on websites - the drive is having problems reading from the media, including the partition table (hence why you don't see the partitions).
AusAbe wrote:
Then I tried EASUS Partition Recovery 5.0.1 but it can't locate a physical or logical partition.
Completely expected - as I said, you do not have a "lost partition".
Stop trying to use the drive - your further attempts could be increasing the degradation of the disk, and are not going to be successful without a different approach requiring further h/w which, as you've mentioned, you have no chance of getting in your remote location.
AusAbe wrote:
I've reviewed hundreds of threads but don't know where to go from here. I know the data is there and the physical components work, I just can't access the files.
Sorry but you're mistaken. You don't
know that the data is still there. At least some parts of the disk are currently unreadable. If this problem has been caused by (for example) contact between head & disk, then some portion of your data might already be lost. Based on your comments above, the situation needs to be treated more seriously than thinking this is just "inaccessible files" i.e. logical corruption - the CRC error is your big clue (look in the Windows System Event Log and I expect you'll see more errors logged).
I expect this isn't the news you wanted but, based on what you said, this would be the advice I'd give to a friend of mine in the situation as you describe it. Of course other forum members might interpret your situation differently and hence give different advice.
Good luck with whatever you decide to do.
[Edited to add: In this context, I'm fairly sure that the reported "CRC Error" is not an
interface (SATA or USB) CRC error, but is actually the application reporting a UNC error i.e. uncorrectably read error - again, you'll be able to confirm this from the Windows System Event Log entries. If instead you see USB errors being logged in the Windows System Event Log, then you could try taking the out of the USB enclosure and attaching it via a different enclosure, but without that extra h/w, you won't be able to attach it to your laptop anyway...]