I have two drives used for SQL backups which for the last week have been acting strange - the free space indicated by windows is far off from what windirstat, etc indicates. There should only be about 60 GB of drive space used and there is about 160. This would match the utilization if the two last backup files were still residing on disk.

SQL server is 2000, OS Server 2003 x64. Running on a VMware 5.0 cluster. OSSEC and McAfee for this system shows clean.

My current plan is to temporarily attach one of these drives this drive to another VM for analysis. Is there anything more I should be looking at? There were a lot of pages on the net when I was looking for documentation on this issue but I haven't found this case described.


Unfortunately even a full reboot did not clear this behavior. I also used process explorer to look for open file handles. No dice.

4 Answers 4


Try chkdsk - if the files didn't get deleted properly due to a crash, the space they used might not be marked as free.

Are the two drives experiencing the same behavior, or is it just one where the numbers are weird?

  • chkdsk is probably my favorite utility.
    – Bigbio2002
    Mar 26, 2012 at 20:02


vssadmin list shadowstorage

from an elevated command prompt, to check if there are any shadow copies taking up your space.


Likely the process is still holding the file space after the file is deleted. Trying to restart the suspected proceses.

  • Thanks for the thought. Forgot to mention I looked at this already. Mar 26, 2012 at 15:38
  • Ah then the only thing I can think of is hidden files. That would be a very interesting issue. I encounter this issue in other OSes however so could not think of anything else in windows.
    – johnshen64
    Mar 26, 2012 at 16:10

In our office we are super big fans of SpaceSniffer http://www.uderzo.it/main_products/space_sniffer/. It can be very helpful for finding folders that contain large amounts of data that you weren't expecting. Not sure if it will help in your situation, if the OS truly doesn't remember the files.

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