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The Windows disk cleanup utility has an option to compress files that aren't used often. Windows also includes the tools needed to uncompress them.
When I used the Windows Disk Cleanup tool, it compressed old files. Is there a program to decompress all files on my PC that have been compressed?
There is indeed a program that will do that.
It's called Microsoft Windows.
What I mean is that you don't need to download or get any additional programs to decompress the files on your system; you can do it right from within Windows.
Here's a folder that has been compressed, displayed in Windows Explorer:
You can tell it's compressed because its name is displayed in blue instead of black.
If we look inside that folder, we can see that all of the files are compressed as well:
Once again, all of the filenames are in blue, indicating that they are compressed.
Before you decompress files, make sure you have enough free space available - the files will take up more room when they are not compressed. If there's not enough room to handle that, then the operation will fail.
Right-click on the compressed folder, click on Properties, and click on Advanced:
As you can see, the Compress contents to save disk space is checked.
Uncheck that and click OK. This will return you to the basic properties for the folder. Click OK here as well.
You can uncompress just the folder and not its contents. Any new files placed in the folder will not be compressed automatically.
However, you can also uncompress everything - the folder and everything inside of it - right now by selecting Apply changes to this folder, subfolders and files. Do that and click OK.
Depending on the size of the folder and its contents, this operation can take a while. Once complete, the folder and everything within it are no longer compressed.
The only problem with this approach is that you need to operate on a compressed folder to uncompress it. If a folder itself is not compressed, but contains many compressed objects, you have to multi-select the objects within the folder to perform the operation above.
If you're not afraid of the command line, however, there's an easier way.
The command-line utility Compact is used to control Windows File compression. Run "compact /?" in a Windows Command Prompt to see a list of its options.
In that Windows Command Prompt, change directory to the directory (aka folder) that contains the compressed folder and run "compact /s":
The "/s" option to compact means operate on all sub-directories as well.
The output shows that in my folder "C:\t", which is not compressed, is the folder "Example Folder" which is. In it are several files which are also compressed.
Worth noting is that the Compact command shows the effects of compression and the space saved for each file. Files which are already compressed - like .mp3 files - do not benefit from additional compression. Files which are basically text - such as .html files - do. Other files benefit to varying degrees based on their contents.
To uncompress the folder and its contents, simply enter the command "compact /s /u" - /s to operate on all sub-directories, and "/u" to uncompress:
A couple of interesting points to note here:
Compact, by default, operates on the current directory. Because we were "in" C:\t, it tried to uncompress it. Because it was not compressed, nothing needed to be done. Because we specified the "/s" option, it then went on to operate on the contents of the folder.
Once again, the uncompressing operation took a little time, but each file was listed as it uncompressed.
After Windows disk cleanup has compressed files, it's often not clear where all of those compressed files are. Therefore, it is quite possible to consider the following:
In other words, change directory to the root of the C: drive and then uncompress everything on it. (You may need to run the Windows Command Prompt "As Administrator" to perform this operation.)
This should work just fine, but a massive operation like this always make me nervous. I'd strongly suggest backing up completely first and double-checking once again that you have lots of free space for the files to uncompress into.
I am not a fan of Windows built-in disk compression. The technology is sound, but its usefulness has declined over time.
Hard disks are huge and relatively inexpensive these days. Even on older machines, it's often more effective to add or replace hard disks that it is to enable compression. Particularly on those older machines, compression and decompression take additional CPU resources that could adversely impact your overall performance.
The other thing that's changed since file system compression was introduced are the files themselves. Many files are compressed already - in fact, many of the very files that you might find taking up much of your hard disk space are.
All of your music files (mp3 and other formats), video files (m4p, mov, wmv and more), and even the latest formats used by Microsoft Office, such as .docx, .xlsx, and similar are all already compressed. File system compression will not compress them by much more; in some cases, it can even make them take up a little more space.
These days, the bottom line is that I advise against letting the clean up utility compress files in the first place unless you really have no other options.