3TB external suddenly becomes 746GB unallocated

Ok, the only thing I can glean and happy about is that the Partition Wizard does not show your external drive as Bad Disk. That is good.

Other than that there is not much to say about the two screenshots.

I think you only ran a quick scan with Partition Recovery Wizard. If so, run a deep scan and post the screenshot of partitions found. ( Do not select any partition/s in it and keep PW grinding till I see the screenshot. If you cancel, no harm but you may have to rerun again to get to that point.)

A deep scan may take a long time. So initiate the scan, and leave it to complete. Attend to other work instead of sitting in front of the computer. (I am hoping it will run for eight hours because I am retiring now and will be back after only eight hours of sleep.:) )

The Partition Recovery Wizard screen shots in my first post were deep scan results. I'll be able to connect to the Win 7 machine later in the week.

Jumanji, I don't think a deep scan with "Partition Wizard" will help in this case. Whether quick or deep, "Partition Wizard" or "TestDisk" scan will be limited to the 746 GB space. As far as i understand the real issue is that OS/Disk Management only reports 746 GB total capacity which is only a quarter of the actual capacity. All recovery tools needs OS API to access disk subsystem so unless "Disk Management" reports 3 TB capacity, partition recovery won't work.

I am not sure whether updating IRST will work but there are more than one success reports across various support forums over net.

How to Fix the 746GB Available of a 3TB Hard Drive IssueServeTheHome ? Server and Workstation Reviews

OK, then PW did not find the correct partitions.

I see Anshad still there and I will solicit his opinion on further course of action.

Let me also think about it as I sleep. Good day till I am back.

EDIT: I didn't see Anshad's post. Thanks Anshad. So what do you propose ? If you think IRST update will help let the OP do it?

I shall see the reference you had given tom morning.

Thanks Anshad. So what do you propose ?

Although i suggested installing version 10.1 of IRST, that is usually needed for internal hard drives which directly connected to the SATA port. USB interface usually don't need to access the SATA controller. However since the docking station is eSATA based, i still have hope for the driver update.

I just had a cursory glance of that article.

In case the existing driver got corrupted will it not be better he cleans it up first by uninstalling it and then installing the latest driver? Or should he go back to that Windows 7 PC and check before doing anything on the Vista PC?

I shall leave it to you Anshad to guide the Op on it.

My personal opinion is he should go back to the Windows 7 PC first and check. Whats the harm if he has to wait for a day or two?

In case the existing driver got corrupted will it not be better he cleans it up first by uninstalling it and then installing the latest driver?

Uninstalling old driver and then updating is the best course of action. Usually the storage driver will be listed as either "Intel Matrix Storage Manager" or "Intel Rapid Storage Technology". Check whether either of them listed under "Control Panel --> Programs" and uninstall if any.

After installing 10.1 , check whether the driver updated correctly as per this guide : Intel Rapid Storage Technology (RST) drivers and Support for Disk Drives Beyond 2.2 TeraBytes (TB)

If updating IRST is not helping, install "Segate Disc Wizard" and check what capacity it detects ( don't partition the disk with "DiscWizard" ).

DiscWizard | Seagate

Or should he go back to that Windows 7 PC and check before doing anything on the Vista PC?

Definitely that should be the first step if the "Windows 7" machine is available for checking. Since he can't access that machine now, let us check for possible software issues in the meantime.

OP said in a week. Definitely heaven's will not come down.

While driver update of the Vista may be OK, I am against any probing the HDD much less with Acronis(Seagate DiscWizard) until it is hooked up to the Windows 7 PC and we know the status-whether it is the PC or the Dock+HDD we will know.

I am off now. One hour sleep cut. I cannot postpone my wakeup time 0600hrs. See you all. Its already today.

jumanji said:

My personal opinion is he should go back to the Windows 7 PC first and check. Whats the harm if he has to wait for a day or two?

Operating below 100% by not having access to the most recent data on the drive. Urgency is not to the point where I'd jeopardize the recovery though, but I'm willing to do what I can right now.

Anshad's suggestion (post #7) worked, IRST update now allows Disk Management to show 2794.52GB (2049GB and 746.52GB unallocated).

WhyAlwaysM3 said:

If detecting the 3TB (so I can then recover all the partitions)

So we seem to be here now. But should I fully uninstall the drivers and reinstall (to bulletproof that aspect)? Driver version shows 10.1.0.1008, 3TB (2794.5GB) shows as unallocated.

Get your rest jumanji.

That is both good and bad news. The good part is we got the full capacity back and the bad part is the disk is detected as unallocated/ MBR partitioned. To my understanding the disk was partitioned under GPT scheme. If the data stored in it is really important, i won't recommend trying any recovery tool before connecting and checking the HDD to a direct SATA port of a desktop machine.

Btw, you can do a quick scan with "Partition Wizard" now. Just don't write a new partition table without checking the disk on another system.

So we seem to be here now. But should I fully uninstall the drivers and reinstall (to bulletproof that aspect)? Driver version shows 10.1.0.1008, 3TB (2794.5GB) shows as unallocated.

No need to mess with the drivers. IRST seems to be updated successfully. Otherwise we won't see the full disk space.