We help IT Professionals succeed at work.

Missing free hard disk space

timb551 asked

I have a sbs 2003 server with missing hard disk space.

On our data partition (107GB) we have 65GB of data on the drive but it is being reported as 90MB free.

I have gone through all the folders and cannot see what is taking up the space.

I have installed windirstat and it has the missing space classifield as unknown. It doesnt allow me to do anything with it.  I have included a screen shot.

Any thoughts on how to get the space back?

Watch Question

Hi tim551

Run a chkdsk /f on the hard drive, then try windirstat again.
Skip the bad sector scanning option.
Do you have any Backup applications running that operate like windows shadow copy? the unknown section might be allocated to an app like shadow copy

Don't know if this helps, however, from this article, if you run WinDirStat as Administrator you will get less <unknown> and more detail.

There are more comments from this article that may assist.
timb551IT Manager


Ok will try both of those and report back.

Shadow copy is turned off.
Gary ColtharpSr. Systems Engineer

Paging space on secondary drive? Granted it shouldnt be 40Gb.... but I would be going to the root of that drive in a command prompt and dir /ah /as *.* to see if there are hidden or system files hogging space.
Hypercat (Deb)President

Check the shadow copy settings - even if it is turned off, if it has been turned on at any point there may be existing shadow copies that haven't been deleted.

Also, in addition to running chkdsk, try running defrag on the partition where the unknown used space exists.
Gary ColtharpSr. Systems Engineer

Did you turn Shadow Copy off or was it already off? You may have a shadow copy cache file that needs to be removed?
timb551IT Manager


How do see if there is any shadow copy stuff there?
I would use TreeSize to get the information about the drive. This will get you a lot clearer image of the drive and where data is being used.

I believe running TreeSize as an admin allows you to see hidden and system files including shadow copy cache files (we use it here when a drive goes bonkers and needs cleaning).


You could also enable Shadow copy and simply review the settings. make the adjustment if Shadow copy is the culprit and then disable it again.
Top Expert 2013
To repeat JRaasumaa's suggestion and add:

Redirected my documents (user folders) do not show the space used. By default they are not accessible by an admin and show 0GB. The pro version of Treesize (free trial) will correctly report that. You must run in administrator mode:
Treesize is also great at locating other large files and/or folders.

There is a recent issue that affects SBS2011:
How to Alleviate Disk Space Pressure Caused By a Large Windows Component Store (WinSxS) Directory

There are some known issues with log files taking up huge amounts of space on SBS 2008, which you may want to review.

Another culprit can be C:\Windows\System32\logfiles\WMI\trace.log You can stop this logging by editing the registry key (if necessary) to 0
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\WMI\GlobalLogger\Start = 0

Exchange will also retain log files and deleted e-mails until you do a full SBS backup or Exchange backup. The backup clears these items but you need to run the SBS native backup or an Exchange aware backup before they are cleared.
timb551IT Manager


Thanks guys

Ive found it.  I have shared the points if thats ok as it was treesize that found it thanks JRaasumaa but it was a hidden profile folder that was taking the space up.  Thanks RobWill.
Top Expert 2013

Thanks timb551Date, glad to hear you were able to resolve.
This is a very common question so I opted to blog and summarize the many "black holes" in SBS that can take up disk space and ways to create more space, for those that follow:

Explore More ContentExplore courses, solutions, and other research materials related to this topic.