Windows explorer displaying wrong free space

Question

I have a 1TB* external HDD which comes out at 931GB total space on windows explorer (run as admin).

When I look at free space it lists only 183GB free with 747GB used. However, there is not this much used space. When using WinDirStat (run as admin) this drive only uses 472GB of space.

I have cleared the shadowstorage down to the latest shadowstorage using DiskCleanup which increased the free space to the 183GB free. Now I can't think of anything else that could be causing this 275GB discrepancy.

I had used this external drive on an old laptop, could there be an issue with that?

Thanks for any advice.

Solution 1

I have finally solved my problem and would like to thank everyone for their help. As I said in my opening statement this external was used on an old PC and for some reason this lead to permissions issues. After going through all the subfolders to change the permissions for the files the drive's used space is now correct on WinDirStat and when selecting all the files and clicking properties.

@Psycogeek - you were correct in saying that MyDefrag shows the files, thanks for that, unfortunately due to the files being in a folder that I had used frequently and had permissions to I wasn't able to determine that they would be missing. Plus 675GB of files is hard to go through :P

@Alexey Ivanov - The files were viewable in windows explorer like you said but WinDirStat and windows explorer apparently do not include files with permissions from an unknown source - thanks for the help.

If anyone else has this problems it could be down to this issue. File explorers and visualisers seem to have trouble examining files that have different permissions - You have to remove the unknown user's permissions and change the permissions to your current system - in my case this was arthur-PC/arthur rather than a long string of characters. As there are already guides for this I will post a link.

http://answers.microsoft.com/en-us/windows/forum/windows_vista-files/how-do-i-change-folder-and-file-permissions/465f2b42-63dd-4486-8dd1-c870290efeed

First answer is correct. - remember to click subgroups and folders, because I did not do this when orginally changing permissions I could view the contents of the folder in windows explorer but not subfolders and you have to click each and every one to gain access to it.

Thank-you to everyone for your help, I hope this answer can help people that might have the same issue.

Arthur

Solution 2

WinDirStat may not be able to open some folders even when run as administrator, for example System Volume Information folder which also consume space.

NTFS has also Alternate data streams feature. It's not widely used, and usually software does not take that into account when displaying file size.
 

• To see how much space is allocated for Shadow Copies, run

  vssadmin List ShadowStorage
  

  Its outputs looks like this:

  Used Shadow Copy Storage space: 27.419 GB (9%)
  Allocated Shadow Copy Storage space: 27.759 GB (9%)
  Maximum Shadow Copy Storage space: 28.237 GB (10%)
  

• To see how much space is used by system, run chkdsk in read-only mode (replace C: with your drive letter):

  chkdsk C:
  

  And look at numbers in lines with in use by the system and occupied by the log file in the report:

  296082431 KB total disk space.
  119089088 KB in 656918 files.
     407696 KB in 80692 indexes.
          0 KB in bad sectors.
     894379 KB in use by the system.
      65536 KB occupied by the log file.
  175691268 KB available on disk.
  

Comments

[Ramhound]

I am going to guess the different is your WinSXS directory. If thats the case the directory size will be reduced automatically. Its also possible you have automatic restoration points enabled. WinDirStat doesn't detect all disk usage: superuser.com/questions/279900/…

[Alvin Wong]

Even if you select all files (including hidden ones) on the root of the drive and view Properties, the size displayed will be smaller than the used space shown for the disk.

[karf]

@Ramhound Can't find a WinSXS directory on the external only on my C: drive. The suggestions on the other page didn't help :( WinDirStat was running as administrator, recyclebin is empty on the external and only has like 2MB on C:, no system protection on the drive, cleared shadow copies, and no system restore points.

[Frank Thomas]

have you emptied your trash?

[karf]

@FrankThomas as far as I can tell it is cleared

[Ramhound]

@karf - I promise you the WinSXS directory does exist on your hdd. You don't want to get rid of it because of system stablity problems caused by removing it.

[Psycogeek]

When all else fails, to see what is on the disk and all hidden/superhidden files, MyDefrag or other defraggers similar will show what is in the clusters themselves. MyDefrag can be "Portable" simple and easy, dont even have to defrag, but move the mouse around after doing an "analisis" and you can see Everything. From that you can see what your not seeing, then provide more info.

[karf]

@Psycogeek Edited to show appropriate usage of admin permissions. Using MyDefrag Now will post results shortly.

[karf]

Shows 600GB of unfragmented along with about 65GB of fragmented, although it only shows fragmented files. This concurs with Windows explorers results though, hopefully this can help.

[Psycogeek]

I dont need the numbers, the idea is for you to see the file items, taking spaces. Did you use the cluster view to see anything odd? (move the mouse around the view see what files are there) It does help to run a re-order (sort) defrag, then everything is in alphabetical. Unmovables are a different color. Hidden recyclers, system restores, $logs, page file, etc are all shown here everytime.

[karf]

Shadow Copy Storage association For volume: (G:)\\?\Volume{b0103e6e-414c-11e1-81d8-5404a6c46233}\ Shadow Copy Storage volume: (G:)\\?\Volume{b0103e6e-414c-11e1-81d8-5404a6c462 33}\ Used Shadow Copy Storage space: 0 B (0%) Allocated Shadow Copy Storage space: 0 B (0%) Maximum Shadow Copy Storage space: 9.315 GB (1%) chkdsk outputs stopped due to errors found

[karf]

after unmounting the drive chkdsk allowed me to continue, results are below: '976758783 KB total disk space. 697675104 KB in 30110 files. 57552 KB in 3472 indexes. 0 KB in bad sectors. 195135 KB in use by the system. 65536 KB occupied by the log file. 278830992 KB available on disk. 4096 bytes in each allocation unit. 244189695 total allocation units on disk. 69707748 allocation units available on disk.'

[karf]

From this it appears that the files are there but just unviewable :/

[Alexey Ivanov]

So you have 665 GB in files, these files should be viewable. Non-viewable space is occupied by the system: indexes 56 MB + log file 64 MB + system 190 MB = 310 MB, it's quite small. So your free space is 931 GB total - 665 GB files = 266 GB, which corresponds to the number reported by chkdsk.

[Alexey Ivanov]

You should always take into account the size of allocation unit, usually 4 KB. That is file system allocates space for files in these increments. File of 1 byte takes 4 KB of disk space; when the file size grows to 4 KB + 1 byte, it takes 8 KB of disk space. Windows Explorer reports both sizes in file properties dialog: Size is the actual size of the file, and Size on disk is how much the file really takes on disk. If you have many small files, then much of disk space is kind of wasted.

[karf]

(dropbox.com/s/dqki1pmdpoimcz6/G2.png) (dropbox.com/s/rl4gg3ux73k6mwi/G.png) One picture shows the windows explorer properties of G: (665GB used) and the other shows the properties of every folder selected in G: (473GB) I don't think its the size on disk stuff, I just somehow can't view the files for some reason.

[Alexey Ivanov]

It's the permission issue: even if you're administrator, you can get “Access denied”. When calculating size of folders, applications usually ignore these errors. When you navigate to that folder, you'll get an error message. If the files are readable but owned by an unknown users, they're included in the size calculations.