Windows 7 : Using Compression and Encryption (part 2) - Compressing Files and Folders

2. Compressing Files and Folders

In addition to compressing an entire drive, Windows 7 allows you to compress files and folders selectively. When you compress a folder, you can elect to compress only the folder and the files it contains, or the folder, its subfolders, and all related files.

2.1. Compressing a file or folder

Any files or folders you create in a compressed folder are compressed automatically. When you move an uncompressed file or folder to a compressed drive or folder, the file or folder is compressed automatically when you are moving between drives. However, if you move an uncompressed file or folder to a compressed folder on the same NTFS drive, the file or folder isn’t compressed automatically and you will need to compress the file or folder manually.

You can compress a file or folder by completing these steps:

1. In Windows Explorer, right-click the file or folder that you want to compress and then select Properties.

2. On the General tab of the Properties dialog box, click Advanced.

3. In the Advanced Attributes dialog box, shown in Figure 3, select the “Compress contents to save disk space” checkbox and then click OK.

4. For an individual file, Windows 7 marks the file as compressed and then compresses it. For a folder, Windows 7 marks the folder as compressed. If a folder contains files or subfolders, Windows 7 displays the Confirm Attribute Changes dialog box, shown in Figure 4:

   • To compress only the folder, select “Apply changes to this folder only” and then click OK. Newly created files in this folder will be compressed.

   • To compress the folder, subfolders, and all related files, select “Apply changes to this folder, subfolders and files” and then click OK. All existing files and newly created files in this folder will be compressed.

Figure 3. Compressing the disk

Figure 4. Choosing the compression options

2.2. Expanding a file or folder to remove compression

If you later decide that you no longer want to compress a folder or file, you can remove compression. Before you do this, you should ensure that the drive has adequate free space to accommodate the expanded files. Typically, you’ll need at least 50 percent more free space on the disk to expand its contents successfully. If a compressed folder currently uses 2 GB of space, this means you’d probably need about 1 GB of free space to expand the folder successfully.

You can expand a file or folder by completing these steps:

1. In Windows Explorer, right-click the file or folder that you want to expand and then select Properties.

2. On the General tab of the related property dialog box, click Advanced.

3. In the Advanced Attributes dialog box, clear the “Compress contents to save disk space” checkbox and click OK twice.

4. For a file, Windows 7 removes compression and expands the file. For a folder, Windows 7 turns off compression for that folder. If the folder contains subfolders or files, Windows 7 displays the Confirm Attribute Changes dialog box, shown in Figure 5:

   • To expand only the folder, select “Apply changes to this folder only” and then click OK. Newly created files in this folder will not be compressed.

   • To expand the folder, subfolders, and all related files, select “Apply changes to this folder, subfolders and files” and then click OK. All existing files and newly created files in this folder will be uncompressed, and newly created files will not be compressed.

Figure 5. Choosing the uncompress options