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Why is my 750GB external hard drive full when it has only 70GB on it?


I’ve a Windows 7 PC. My browser is IE 9. I’m using an external hard drive to
backup files and hold files from a previous personal computer. My computer page
which shows the various drives inaccurately shows my 750 GB external hard drive
is full. Though I’ve added up all the files and there’s only 70 GB on it. I
deleted 10 GB of duplicate files and it still reads “full” with only a few MB

In this excerpt from
Answercast #97
I look at a hard drive that is mysteriously showing full.
Perhaps it’s hidden files.


External hard dive is full

So there are a number of things that could be going on here.

The first thing that comes to mind is: have you ever emptied your Recycle bin?

When you delete files, by default they often get placed into a Recycle bin. What that means is the file is not physically deleted; the space is not immediately freed. It’s placed in this Recycle bin in case you change your mind later. You can then go back there and undelete the file from the Recycle bin. It’s only when you empty the Recycle bin that the files are permanently deleted and the space they take up is completely released back to the system.

So, first thing I would have you do is – empty your Recycle bin.

Look for hidden files

Second thing I would have you do is, in Windows Explorer, uncheck the option that says “Don’t display hidden files” or to put it the other way, make sure that hidden files are being displayed.

My guess is that there’s actually a lot more on that external hard drive than you think and that those files are what’s taking up all that space. Make sure that option is turned off so that Windows Explorer will make all those files visible.

There’s a bunch of files that are hidden by default in Windows and depending on how that hard drive was filled originally, with whatever it was filled with, it is very possible there’s a bunch of stuff on there.

What’s taking up space

Finally the other thing that I’m going to throw at you is an article I wrote a while back called, “Where’s my disk space going?

That article references a tool called TreeSize, which will allow you to actually see where, on that hard drive, that space is being taken up – which folder has all of these files that are taking up so much space.

Even if you don’t turn on the view hidden files option in Windows Explorer, Tree Size is going to show you all of those folders that it can find on that hard drive. My guess, like I said earlier, is that there’s a bunch more on that hard drive that you didn’t realize was there.

Using Tree Size, you can identify where that all that space is going and then take the appropriate action depending on what you find.

(Transcript lightly edited for readability.)

End of Answercast 97 Back to – Audio Segment

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6 comments on “Why is my 750GB external hard drive full when it has only 70GB on it?”

  1. I agree with Mark J CCleaner is a great tool for cleaning your history/cache, CCleaner cleans stuff that the windows built in History/cache cleaner don’t clean.

    Although i would keep away from the Registry cleaner part of it, 2 dead computers, no backups and no reinstall disk taught me a lesson about using Registry cleaners.

    Backups good, registry cleaners bad.

  2. I don’t know about the latest operating systems, but “back in the day” there was a fairly small limit on the number of directory entries allowed in the root directory. Back then you could get a “disk full” message with a small portion of the disk actually used. I think the number was something like 252 entries. Again, I don’t know about Win 7 and NTFS limits.

  3. A very easy way to find the space used by hidden files is to open a command shell, locate to the directory root and type

    dir /a:h /s

    This will list all of the hidden files, their individual sizes, and the total space for all hidden files.

  4. Check on how the hard drive is formatted / partitioned.
    I bought a new LaCie 2Tb drive which only showed 500Gb. The problem was that it had been auto formatted with a hidden 1.5Tb partition.

  5. I’m using XP Pro but this might work with Win7. Go to Control Panel, Computer Management, Disk Management and look at the disk in question to see if there are other partitions. If you fine any, find what’s on them before doing anything. You might be surprised.


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