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I have a Win7 laptop with a 750Gig C: drive. It came partitioned with 714Gig usable from manufacturer. I installed programs, music files, etc up to 285 gigs. As of a few weeks ago it showed 285 Gigs. Two weeks of house guests later and it shows HD is full. I deleted some files but it still shows 652 Gigs on this drive while there are only 285 Gigs on drive. Relevant details:

  1. I am Administrator on laptop and have fair knowledge of what I am doing.
  2. I did not restore from backup, restore from mirror, upgrade HD's or anything else that would have touched the partition structure. Just daily use as imaging machine and web.
  3. I have checked partitions under disk administrator - no change, still partitioned with 714Gigs usable.
  4. Have looked through computer C drive by hand showing Hidden files and folders - no change.
  5. I have used JDisk Report to double check - it shows I have only 285 Gigs on C drive.
  6. I triple checked with TreeSize run as Administrator and it also shows 285 Gigs on C drive - yet Windows 7 still shows almost full.
  7. I used Windows 7 Utilities to Check for Disk Errors, and Defragged the drive. No errors shown and no change after Defrag.
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Does your C drive say 750 (or a little less gigs) or does the sticker on your laptop say 750gig? Perhaps there are unallocated partitions? Click the start button and type chkdsk and click chkdsk.exe. This will open drive management. Could you post a screenshot of that window? If there is any unallocated space, just allocate it and enjoy your extra space. – Tycho91 Mar 31 '13 at 12:12
Any way to see, yes when playing blind mans bluff with hard drives , anything that can view the data that is stored in the actual cluster things , is the only way to know sometimes. lots of hidden things even via the system. If you dont get a visual answer in the drive management and via the data of the chkdsk as above. try something that views clusters, like many defraggers. a free one is MyDefrag, moving your mouse around you can painstakingly see everything . sometimes things you wish you never saw :-) – Psycogeek Mar 31 '13 at 14:01
What's the actual make/model of your drive? What's shown in Windows' Disk Management? What size is reported in the BIOS? – Ƭᴇcʜιᴇ007 Mar 31 '13 at 14:27
I think you're confusing hard drives with partitions. You can certainly have a 750GB hard drive that has a partition that is full with only 315GiB used. What does the disk manager say? – David Schwartz Apr 1 '13 at 6:19
Did you empty the recycle bin after deleting all the junk? – Mark Henderson Sep 27 '13 at 9:38

Use TreeSizeFree and run it as admin (this is very important to see hidden/system files and folders).

Now you see a nice overview of what is using the HDD space:

enter image description here

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Thank you for the idea - TreeSize is a nice little program. Unfortunately it only told me what windows explorer and a spreadsheet told me - I have a 714Gig Partition that windows shows only has 62.Gigs free (deleted stuff since first post). According to Windows Explorer, Treesize (run as administrator) and JDisk Report there is only 285.5Gigs of data on the disk. So... What is using up the other 366Gigs? Not in any hidden file, folder, or partition. – Chris Kelly Apr 1 '13 at 21:03
@Chris Kelly run chkdsk /R /F, maybe the NTFS metadata are damaged and show you wrong data. – magicandre1981 Apr 2 '13 at 4:19
this, and most other tools, won't show the actual disk consumption because of "Windows Side By Side" or winsxs, see… – matt wilkie Apr 30 '13 at 16:44

Check your system restore points. If they build up, you won't see them but they can eat a very large portion of the drive. You can configure your restore settings to control how much disk space they are allowed to use:

  1. Click right on computer and select properties
  2. Click System protection
  3. Select configure
  4. Choose max usage to limit how much drive space is allowed.
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But why would system restore points have eaten up 367 GB in two weeks? – Scott Dec 12 '15 at 16:49

You can try sdelete to delete information from "unallocated" space. This worked for me on a 800 GB server that was "full", but only 650 was actually being used. This happens because as files are "deleted", they aren't deleted, the space is marked as "unallocated" (the deleted information is still there until new information overwrites the "deleted" data). sdelete is a MS toll that removes the information, and marks the locations as free.

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Once a file is really deleted (not just sent to a recycle bin) and the FileSystem marks it as deleted, then the space is now available for new files and is free space, no need to use any special program. If your FS isn't counting free space correctly then chkdsk should fix it. SDelete is only a secure delete tool, that overwrites files or free space – Xen2050 Jan 9 '15 at 23:34

My friend told me that his disk D: has shown nearly full but there is little data, because he chose disk D: to make backups.

He had turned on the schedule, so I turned off the schedule and cleaned all the backups. After that, I deleted the system image file.

Now everything is ok. Hope this will help you.

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Please, don't do that. Make backups and make them on a separate drive. When something fails unexpectedly you'll be screwed without backups. – gronostaj Aug 19 '14 at 21:48
You deleted your friend's backups and his system image file, and turned off his automatic backups?  I'm glad you're not my friend. – Scott Dec 12 '15 at 16:45

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