External HDD - K:/ is not accessible

I have 2 SATA hard drives inserted into a docking station connected to my laptop with USB
both were working fine until a week ago then both stopped working altogether
Today I switched everything off and tried re-seating them one by one
One came up as working fine but the second one came up that it was unformatted
Knowing I have important files on the disc I have no intention of formatting it
I tried again and now get the following error:
K:/ is not accessible. The disc structure is corrupted and unreadable
Could someone please advise on recovery
Thank you

Go to disk management and check what it is showing.
Your disk may have changed from NTFS to RAW.

If it is the case, there are many programs which can recover data from RAW HDD
such as Stellar Phoenix Windows Data Recovery (it is a shareware).

mvthakar said:

Go to disk management and check what it is showing.
Your disk may have changed from NTFS to RAW.

If it is the case, there are many programs which can recover data from RAW HDD
such as Stellar Phoenix Windows Data Recovery (it is a shareware).

Thanks Mvthakar. It seems your right with your diagnosis
but I tried Stellar Phoenix but was unsuccessful
Can there be another solution?

You can try PartitionGuru free Free partition manager, file recovery tool and Windows backup software - PartitionGuru Free

GokAy said:

You can try PartitionGuru free Free partition manager, file recovery tool and Windows backup software - PartitionGuru Free

Thanks but that hasn't worked. It stopped with an error message and wouldn't continue scanning.
Is ther not some way of changing it back from RAW to NTFS?

Did you try a partition or file recovery? Try partition if you haven't.

If that doesn't work, you can try to recover the partition with TestDisk - Partition Recovery and File Undelete but this one is abot advanced. Here is a step by step tutorial for TestDisk TestDisk Step By Step - CGSecurity.

If that fails too, try PhotoRec PhotoRec - Digital Picture and File Recovery. Provided with TestDisk above.

Two SATA drives in dock.

One is now working fine. Make/model No/ Capacity ? Info required.

One is throwing an error message. Make/Model/ capacity? Info required.

Now remove the one working fine and keep it aside far away beyond your reach..Note: Always "safely remove"

Put the one not working into that slot. Check and tell us what happens.

Also post a screenshot of how it appears in Windows Disk Management. ( Please remove all other external drives/pendrives/ USB hubs/ USB printer etc., except your USB Keyboard and mouse. Only your dock and the non-working drive in the working slot, as we know, of the dock.) Disk Management - Post a Screen Capture Image

jumanji said:

Two SATA drives in dock.

One is now working fine. Make/model No/ Capacity ? Info required.

One is throwing an error message. Make/Model/ capacity? Info required.

Now remove the one working fine and keep it aside far away beyond your reach..Note: Always "safely remove"

Put the one not working into that slot. Check and tell us what happens.

Also post a screenshot of how it appears in Windows Disk Management. ( Please remove all other external drives/pendrives/ USB hubs/ USB printer etc., except your USB Keyboard and mouse. Only your dock and the non-working drive in the working slot, as we know, of the dock.) Disk Management - Post a Screen Capture Image

Thanks
working one is a Seagate Barracuda ST 1000DM003 - 1000GB
The faulty one is Toshiba DT01ACA100 Capacity 1.0TB. It's not so old, its dated Aug 2013

Well, I suggest you should try some famous data recovery softwares.
One such example is EaseUS Data Recovery.