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How to Fix: New 3TB Drive Only Shows 746GB

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    New 3TB Drive Only Shows 746GB

    I’m sure that many people like me have encountered the following issue: when I install a new 3TB hard disk into computer, I can only see 746GB (not 745GB or 747GB, but exactly 746GB) in my Windows Explorer as well as Disk Management.

    And here, if we Google “3TB drive shows 746GB”, we will find many users have encountered the same issue. Let’s see some examples.

    I bought the Seagate barracuda 3TB and it shows as 746GB on my Windows Vista SP2 32-bit in GPT mode. I have asked this problem at Seagate forum and the one guy who replied didn't know how to solve it. I am using the 3TB Seagate drive in my Rosewill RX-358-U3B enclosure, and I have read that a Hitachi 3TB had no compatibility issues in that particular enclosure. Does anyone know how to have my computer realize that the Seagate drive is 3TB?

    Seagate 3TB (ST3000DM001) in a Thermaltake BlacX (USB+E-Sata) docking station that had 5 partitions spread over the actual drive's capacity, now registers as 746.5GB unallocated. I connected the dock to a Win 7 desktop through E-Sata and copied files off of the external successfully. Shortly after I plug it into a Vista x64 laptop (machine it has been used with predominately and problem free) and I get back to business. A few minutes later I notice the partitions aren't visible/746GB unallocated. Disk Management, TestDisk, PhotoRec, Partition Guru, etc all display 746GB instead of 3TB. The Vista laptop is the only machine I have access to at the moment so the scans/tests are being done with that.

    What’s going wrong here?
    Why we cannot see the full disk of 3TB hard disk?
    Is it possible to solve this problem effectively and easily?

    How to Fix: 3TB Drives Only Shows 746GB

    746GB available of the 3TB drive According to a survey, we find many users don’t know what causes this to happen. And most people blame on their drive manufactures since they think they bought the wrong hard drive. In general, whether you are using Hitachi, Western Digital, Seagate, or Samsung drives, you might encounter this problem. It is a fairly common issue. However, do you know how to solve this issue?

    Now, 3 major reasons as well as corresponding solutions will be introduced. Knowing the exact reason, you can solve the problem with ease.

    Reason 1: you are using the old version of Intel® Rapid Storage Technology driver

    A study saying that Intel® Rapid Storage Technology (RST) version of is the culprit behind the 746GB available of the 3TB drive issue. For 3TB drive support, one should look to Intel RST 10.1 and newer. However, before you upgrade Intel® Rapid Storage Technology driver to the latest version, you had better know more information about RST.

    RST-2.8GB-and-Disk-Management 746GB

    Intel® Rapid Storage Technology (RST), a program developed by Intel, can offer new levels of protection, performance, and expandability for desktop and mobile platforms. Besides, this program has added support for next generation PCIe storage devices with transfer speeds up to 1 GB/s that maximizes storage performance and improves response time for everyday usages like photo editing, video loading, and office productivity. And, Intel Rapid Storage Technology provides Intel® Smart Response technology to recognize and automatically store your most frequently used applications and data into a high performance SSD while giving you full access to the large storage capacity of a hard disk drive (HDD). In a word, with this program, you can take advantage of enhanced performance and lower power consumption when using one or multiple hard drives.

    Step 1: Download the latest version of Intel’s Rapid Storage Technology (Intel RST) drivers from Intel’s site.

    Step 2: Install the Intel RST drivers on computer. Note: If your computer is unable to connect to a network, you can turn to the manufacturer’s installation media which often have older versions of things like Intel RST drivers.

    Step 3: After upgrading to the latest RST version, you can open Computer Management window again, and now you can see all free space of your drive.

    For more information about this situation, please see HOW TO FIX THE 746GB AVAILABLE OF A 3TB HARD DRIVE ISSUE.

    Note: What if you are using AMD instead of Intel? Suppose that you are using AMD and here are the specs:
    amd intel Amd Phenom II x4 925 @ 3ghz w/corsair H50 water cooler
    Gigabyte 770TA-UD3 mobo
    400GB SATA HDD for OS,
    Windows 7 ult x64
    In this case, what should you do since Intel RST would be senseless for you? At this time, if you want to solve this issue, you might try updating the chipset and any SATA/ RAID drivers you can find.

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    Reason 2: you format your 3TB drive in MBR by mistake

    MBR GPT Hard drives are, as you know, typically formatted in MBR (Master Boot Record) or GPT (GUID Partition Table). However, do you know the difference between MBR and GPT? For instance, MBR disk can only support 2TB hard drive. Here, you can see this video (MBR Disk VS. GPT Disk) to get more information about the two kinds of disks. Now, in order to use and manage the 3TB hard drive, you should change it to GPT disk. Detailed steps are shown below.

    When it comes to converting MBR disk to GPT, you can turn to Windows built-in disk management tool as well as third-party free partition tool.

    • Method one: turn to Windows built-in disk management tool

    • Step 1: Right-click “My Computer” and choose “Manage -> Storage -> Disk Management”.

      Step 2: If the MBR hard disk which you want to convert to GPT disk contains any volumes, right-click any volumes on the disk and then click “Delete Volume” to delete all volumes.

      Step 3: Right-click the MBR disk that you want to change, and then click “Convert to GPT disk”.

      However, is it possible to convert MBR disk to GPT without data loss?

      Want to know the best part?

    • Method two: turn to third-party partition tool

    Here, to complete this conversion without data loss, you can try using free MiniTool Partition Wizard since it offers high security as well as excellent performance.

    Step 1: Download this professional free partition management tool from its official website, install it on computer, and launch it.

    convert MBR disk to GPT

    Step 2: Right-click the MBR disk, and choose “Convert MBR Disk to GPT Disk” function from the pop-up menu or from the left action panel.

    Step 3: Click on “Apply” button and tap “Yes” in the pop-up prompt interface to start converting.

    Thus, all work has been done. After that, you might make full use of the 3TB storage space.

    Tips: if the 3TB MBR disk contains system partition, you are not allowed to convert it to GPT disk since this conversion will cause your system to be unbootable.

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    Reason 3: SATA ports

    Some users who connect their internal hard drive to computer via a USB enclosure might encounter the 746GB available of the 3TB drive issue. What should they do?

    In general, there are some USB enclosures have a 2TiB limit, irrespective of the partition type. At this time, users can try connecting external hard drive to computer via SATA.

    Bottom line
    After seeing the three major reasons, you might have a basic understanding of how to solve the 746GB available of the 3TB drive issue. In a word, if a new 3TB hard drive only shows 746GB, you may convert it to GPT disk, or upgrade your Intel® Rapid Storage Technology (RST). Besides, if it’s an external disk, you had better connect it to computer via SATA.

    However, if you want to perfectly make full use of the 3TB storage space, you had better do some corresponding partition management like create partition, extend partition, clone partition, etc. Here, we will show a free partition management program which might be unfamiliar to you but can help you a lot.

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    3TB Hard Drive Management

    As is well known, we can divide our hard drive into several independent partitions to protect data, keep running multiple operating systems on the same disk, and improve performance. However, how to manage partitions to maximize the performance of our computer? Here, you can try using MiniTool Partition Wizard to perfectly manage hard drive partitions.

    With this professional partition management freeware, you can easily and quickly create partition, move/resize partition, extend partition, delete partition, format partition, copy disk, and more. And, we take “Copy Disk” for example to show more information about this tool.

    Disk Clone

    If you want to upgrade small old hard disk to larger newer one without reinstalling Windows and all other installed programs or make a backup for the disk which saves significant files, you can turn to the “Copy Disk” feature. Detailed steps are shown here.


    Step 1: In the main window of MiniTool Partition Wizard, select the disk which needs copying and then click “Disk > Copy”, or activate “Copy Disk” function from left panel to get the following interface.


    Step 2: Select the disk that will save the copy of the source disk as the target disk and then click “Next” button.

    (1) The target disk should be large enough to hold all content on source disk.

    (2) It is recommended to backup all important data on this target disk in advance, because all its data will be deleted.

    Step 3: Choose a copying method to decide the layout of target disk and then click “Next” button.

    Tips, it is highly suggested that SSD and advanced format HDD users keep checking the option “Force to align partitions to 1MB”.

    Step 4: Click “Finish” button to go back to the main interface.

    Step 5: Click “Apply” button on the top left corner to apply all pending operations.

    Note: if you are copying system disk, you will be asked to restart computer. Just do as told.

    In a word, if you are troubled by partitioning problems, you can ask MiniTool Partition Wizard for help.

    Next, we want to show another excellent tool for users who successfully use 3TB hard drive.

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    3TB Hard Drive Data Recovery

    No doubt, users store massive important data including business data, working documents, precious pictures and some personal data on their hard drive. However, data stored on hard drive are not safe all the time, and data loss caused by various subjective or objective reasons happens from time to time. To be specific, users accidentally delete partitions or data; and users format their partition by mistake; and hard drive is infected with a virus.

    So well, it gets better with a proper data recovery tool. And, if you have no idea about data recovery solution, you can try using MiniTool Power Data Recovery.


    The above window is the main interface of this professional data recovery tool. Five relatively independent data recovery modules are listed here, and each of them focuses on different data loss scenario.

    Undelete Recovery recovers deleted data and files.
    Lost Partition Recovery focuses on recovering data from deleted or lost partition.
    Damaged Partition Recovery supports retrieving data from damaged, formatted and RAW partition.
    Digital Media Recovery helps to recover data from digital media in the event of any problems occurring.
    CD/DVD Recovery is designed to recover data from CD&DVD disk.

    You only need to select a suitable recovery module according to actual needs to recover lost data. After that, you will be given detailed operating prompts. Just do as told. What’s more, this tool can keep data safe all the time even in case of sudden power outages. So, you can recover lost data from hard drive without affecting the original data.

    Tips: The free edition could recover only 1GB data, please select a paid edition to break the limitation.

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    Have you ever encountered the 746GB available of the 3TB drive issue? Do you know how to solve this issue effectively and easily? Now, you can find detailed solutions in this article. Besides, this article shows how to perfectly manage hard drive partitions and carry out hard drive data recovery. If you have other solutions for this problem (3TB drive shows 746GB), welcome posting it under this essay!