A couple of days ago I had a strange issue with my computer running Windows XP. The C: drive, with a capacity of approx. 9 GB was showing as if the used space was 7 GB. But I was sure that it could not be so. To make sure, I selected all the folders and files within C: and checked the size. It showed a size of around 4.5 GB. Now I knew something was definitely wrong. I rechecked the sizes and again the same results.
My first suspicion was that some virus must be at work. I must tell you here that I DON’T use any sort of antivirus programs. I was using one long time back but somehow I felt that the antivirus program was more of an annoyance rather than being helpful. I know that any sane person will frown at me for being connected to the Internet and still not using an antivirus. But believe me, I have not had any sort of problems till date (Maybe I am just being lucky). That does not mean to say I advice others also to do the same. It is just a matter of preference.
Ok, back to the issue in hand. I tried hard to find a reason for the abnormal behaviour but could not find a solution. So I did the next obvious thing of searching the web. A little research on the web showed that lot of people have faced the same problem. But most of the solutions were only talking about how files occupy whole clusters and so the space occupied by files can be more than the size of the file itself. While that is true, it definitely was not the reason in my case. A difference of say 50MB or even 500 MB (depending on the number of files in the disk) can probably be explained with the above reasoning. Then again my disk uses the NTFS file system and so this explanation does not hold good for a difference of around 2.5 GB on an NTFS disk. There must be something else.
Suddenly I remembered reading somewhere that the space occupied by the System Restore feature of Windows XP would not be evident easily. I also remembered that while checking the size of folders in C:, there was this folder called ‘System Volume Information’ which showed a size of ’0′ bytes and when tried to open it showed an ‘Access is denied‘ message. (Please note that this folder will be visible only if you disable ‘Hide protected operating system files’ in the folder view options.)
I then checked the System Restore settings for C:. It showed that I had set it to use a disk space of around 2.5 GB. I had now found where my 2.5 GB space was hiding. Frankly, I don’t remember when or why I had set the System Restore setting so high. Setting a higher System Restore space will allow Windows to remember a higher number of Restore points but I feel we don’t need that many restore points. So I reduced the space to 500MB which caused some restore points to be deleted.
I again checked the usage data of C: and as expected it showed around 5 GB which is what I was looking for.
So, if you face a situation like this, do remember to check your System Restore settings.