Do you ever wondering why the free disk space on your system drive (typically C:\ drive) always shrinking and become lesser and lesser? Even without installing new programs or downloading big files from Internet, the used space in local disk drive been increasing and become larger without reason, even uninstalling some software programs does not help to reduce or control amount of space used.

It’s unbelievable that Vista system itself unable to keep consistent usage rate of disk space and keep shrinking available amount of free space. In fact, the issue of unreasonable small and shrinking free space has been one of the top question for Windows Vista. There are various possible reasons for ever increasing disk space usage by Vista. Use the following tips and tricks to identify and find out why the disk space keep reducing and shrinking, which processes or programs that take up huge amount of disk space, and how to fix the low running space problem.

But note that some of the tips involve system tweaking and optimization. Vista enables and turns on these processes and programs not without reason. In fact, some of the processes is important for improved system speed. Thus, it’s recommended to try out whether settings best suit your system before implementing the suggestions to recover and reclaim disk space in Vista.

Some of the big disk space occupiers are by the following processes and its associated files:

hiberfil.sys Hibernation File

hiberfil.sys is a hidden system file in system drive, which has the same size with the amount of physical memory (RAM). hiberfil.sys is used to store state of system memory that computer goes into hibernation mode so that the last used state can be restored when the computer is powered on again. If you’re not using hibernation mode, disable hibernation mode and delete hiberfil.sys file will save users a few gigabytes of space. If the hiberfil.sys still exists after hibernation feature is turned off, you can safely delete the file.

pagefile.sys Virtual Memory Paging File

All Windows operating system uses virtual memory paging file for storing crucial system data when physical memory (RAM) running out of space. Typically, Windows, including Vista by default set the system managed paging file size to 1.5 times the size of system memory, and automatically adjust the size depending on system usage. Unfortunately, the size of pagefile.sys generally getting bigger and bigger. For system with large RAM memory, it’s possible to reduce or even delete pagefile.sys file.

For users with just 512 MB or 1 GB, it’s recommended to keep the system recommended virtual memory paging file. If you want to make more free space available in system drive (C:\), it’s possible to move the pagefile.sys to another drive, or set the maximum size for the pagefile.sys paging file, typically at 1.5 times the size of memory.

If your system has memory of 2G and above, it’s possible to turn off virtual memory and set no paging file at all. In fact, by doing so, Windows will probably run at faster speed. To do so, refer to guidi to manage, change or set paging file size in Vista.

Application and Program Cache of Superfetch Feature

Windows SuperFetch loads and caches user programs and startup applications into memory so that they will be launched faster. The prefetch is stored on hard disk, which can be deleted. To delete the prefetch cached by SuperFetch, delete all files inside “C:\Windows\prefetch” folder.

Temporary Files Created by Running Programs

Most temporary files is created and stored in “\Windows\Temp” folder or “Temp” directory under each and every user profile. To delete the temporary files, remove all files and folders under “C:\Windows\Temp” folder and “C:\Users\[logged on user name]\AppData\Local\Temp” folder.

Temporary Internet Files or Cache Stored by IE, FireFox and other Web Browsers

The temporary Internet files or cache can grow bigger and bigger over time. Deletion method differs by each different web browsers. For IE, go to “Internet Options”, delete delete “Temporary Internet Files” and “Cookies”. For Firefox, click on “Clear Private Data” and delete “Cache” and “Cookies”.

System Restore System Volume Information Folder

System Volume Information system folder, hidden in every disk drive, stores backup copy of data for system restore, known as Volume Shadow Copy in Windows Vista. Volume Shadow Copy uses snapshot method to record state of files at specific point of time and saves it as a restore point, automatically or manually.

There are reported issues that the data storage for System Restore and Shadow Copy grows beyond limit without bound, potentially causing hard disk to run out of space. Users can set or reduce that space limit that is used by System Restore and Shadow Copy to reclaim and recover the space. Or users can delete all old but latest restore points, or disable System Restore and Volume Shadow Copy if not using it. (Note: Will affect Previous Versions feature too.)

Backup Copy of Files Created by Vista SP1 or Other Updates

Some updates and Windows Vista Service Pack 1 backups original system files so that users can rollback or revert to original version when they uninstall the service pack or updates. Microsoft has prepared a tool to remove these backup RTM files after installing Service Pack 1.

Windows System System Logs and Event Logs Files

Windows Vista keeps several log files under the “\Windows\System32\LogFiles” folder. Delete the files and folders inside the “LogFiles” folder to save some disk space, albeit not many.

Other Log Files and Temporary Files

There are other temp files, log files and some other unneeded junk files created over the time by various application software. Use the Vista Junk Cleaner batch script to remove these unnecessary files. Users can even schedule the cleaning process to run automatically to the deletion.

Unused or Unneeded System Files and Preinstalled Files

The default installation of Windows Vista also includes lots of built-in freebies, files, programs and documents that users never need to use or want, such as default background wallpaper and video files. These files can be deleted and removed to further slim down the Vista and free up the disk space. But note that removal of some system files may cause system instability. To do this, see guide to recover space by slim down Vista.