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I have a 2TB drive on Windows 2003. I copied 120GB of data onto it. It is now showing only 840GB of free space. It's like it knows it's a 2TB drive, but only 1TB is available to me. Why would this be?

The drive (Disk I) is partitioned to 2TB.

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migrated from Dec 17 '10 at 10:43

This question came from our site for system and network administrators.

The simple answer from the screenshots shown is that he hasn't selected all the files on I: when he brought up the properties. There are probably some hidden folders/files there or it could be that you don't have permissions to list all the subfolders. But basically there are 1000GB of files on the disk somewhere, not just 200GB

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I have included hidden folders. The drive size dropped immediately after I'd copied only a few GB of files onto it. – seanyboy Dec 17 '10 at 11:23
@seanyboy what do you mean the "drive size" dropped? Do you mean the free space on the drive increased dramatically, or the actual logical size of the disk decreased? – Breakthrough May 9 '12 at 18:37

Mind showing us a screen capture of the disk in disk management? It sounds strange to me...

Disk management is located in Control Panel | Administrative Tools | Computer managmeent

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I have added screenshot as requested. – seanyboy Dec 17 '10 at 11:08
I think it looks legitimate to me. run chkdsk on the disk and see if there is any sector got loose. Sounds like some filesystem error if you can't find a file that occupies the space. You could perhaps format it and copy the file again in that case. – bubu Dec 17 '10 at 11:15
The drive is showing a huge number of bad sectors. I'll swap it out, see what happens. – seanyboy Dec 17 '10 at 11:28
So i guess that's the reason.. these days if you had bad sectors, it is probably best to just retire the drive. I am interested though, that 2TB drives are a relatively recent breed... Why are there so many bad sectors? problem with vibration/storage/usage? – bubu Dec 17 '10 at 11:31
@seanyboy the disk format will only report bad sectors if you do a full format, which essentially does the same thing as a quick formatting the drive, followed by running chkdsk I: /R (which scans the disk surface for bad sectors). – Breakthrough May 9 '12 at 18:38

I would recommend going through these steps. Check drive space after each step.
1. Empty recycle bin. Recycle bin does occupy drive space.
2. Check drive for errors: chkdsk i: /r /f
3. Remove all but recent system restore snapshots for the drive.
4. Use disk cleanup to delete any unnecessary data if found.
5. Use a tool like SpaceSniffer to visually check what is occupying the space.

Personally, I don't see how bad sectors could cause drive space being reported incorrectly.

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