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Why does my hard drive appear smaller than its capacity?

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Last Modified: 2020-02-19
I have a 3.0TB WD hard drive.   When I connect it to my computer, it appears to have only 745GB.
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Dr. KlahnPrincipal Software Engineer
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Commented:
Bring up Disk Management and look at the partitions on the drive.  Chances are it has been previously formatted and a partition remains on it.

It's also possible that it's a used drive with defects and somebody did a high cut on it to hide the defective area, but this is exceedingly unlikely.
Benjamin LuSAP/ERP Data Processing
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Commented:
If you are using win7 OS, just use disk management to change 3T hard disk to GPT.
If it's MBR, system will split it as 2T and 745GB due to limitation.

Author

Commented:
I am using Windows 10 Pro 64-bit.   Does this make a difference?
Fractional CTO
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Distinguished Expert 2019
Commented:
This is almost always a disk controller issue, where controller is the chip interfacing with the disk, usually in an external enclosure of some sort.

Many of the old controllers top out at 2G, so any drive larger than 2G will show random sizes.

Especially when you say "you connect it to your computer", which implies a disk dock.

If you're using an external drive dock, check with the manufacturer for maximum supported drive size.
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Commented:
Your question, suggests you connected it elsewhere and saw a different result.

Is it connecting via A sata port, or is it a USB connected external drive?

diskpart is another way, device management to see what, how the drive is recognized.
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Commented:
post a screenshot of disk management,
here's how to check if the drive is gpt :
Locate the disk you want to check in the Disk Management window.
Right-click it and select “Properties.” Click over to the “Volumes” tab.
To the right of “Partition style,” you'll see either “Master Boot Record (MBR)” or “GUID Partition Table (GPT),” depending on which the disk is using

Author

Commented:
The external drive enclosure was the problem.   I connected the drive to the SATA connection in another computer, extended the volume and now I have the entire disk available.

Thanks to all.
David FavorFractional CTO
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Commented:
Glad you got this working!