Disk Space Cleanup Tip: Use NTFS Compression

Many folks are familiar with the concept of zipping files or folders in order to reduce their size. However, Windows has the built-in ability to compress folders and files in a manner that is very transparent.

Why NTFS Compression?

As alluded to above, the biggest advantage of using NTFS compression is its transparency. There’s no need to compress and decompress manually like with stand-alone utilities such as WinZip, etc. Once applied, NTFS compression and decompression occurs automatically, without the need for any user intervention.

NTFS compression is also very flexible in terms of its scope – it can be applied to a single file, one or more folders, or an entire disk drive (NTFS volume).

Tip: As its name implies, NTFS compression is supported only on NTFS file systems (e.g. it won’t work with FAT32, for example). Not sure what type of file system you have? Just right-click a drive in Windows Explorer and select Properties from the resulting pop-up menu. The file system type will be displayed in the General tab of the Properties window.

When to Use NTFS Compression

Some file types compress better than others. NTFS compression is well-suited to a range of file types, including:

  • Documents, such as those produced by Microsoft Office
  • Text files such as as log files, configuration files, XML data, and many others
  • Uncompressed image files (such as bitmap images)

When NOT to Use NTFS Compression

It’s important to note that NTFS compression can cause a decrease in performance with working with NTFS-compressed files. This happens because Windows is automatically decompressing files for you behind the scenes whenever you open them. When you close the file, Windows then compresses it again. This process does consume some amount of computing resources (primarily CPU time), making NTFS compression more suitable to folders and files that are infrequently accessed.

NTFS compression also isn’t well-suited to all file types. For example, many image file formats (such as JPEG, PNG, etc.) are already compressed and won’t benefit much (if at all) from NTFS compression. The same is true for some video file formats, zipped files, program installers, etc.

Compressing an Entire Drive

You must be logged on as an administrator or a member of the Administrators group to complete this procedure. To compressing an NTFS volume:

  1. Click Start, then click My Computer.
  2. Right-click the volume you want to compress, and then click Properties.
  3. On the General tab, click to select the Compress Volume to save disk space check box, and then click OK.
  4. In Confirm Attribute Changes, click the option you want.

Compressing Individual Files or Folders

  1. Click Start, and then click My Computer.
  2. Double-click the NTFS Volume that contains the folder or folders you want to compress.
  3. Right-click the file or folder you want to compress, and then click Properties.
  4. On the General tab, click Advanced.
  5. Click to select the Compress contents to save disk space check box, and then click OK.
  6. In the Properties dialog box, click OK.
  7. In Confirm Attribute Changes, click the option you want.

Finally, a key component of using any compression mechanism effectively is understanding how your disk space is currently being allocated. FolderSizes can help you to understand precisely which files and folders are taking up the most space, as well as identify logical compression candidates (e.g. large folders, old files, document file types, etc.).