You may download files that need unzipped. This means there are one or more files that are held up in a zipped up folder. The folder must be unzipped to be used. Why Do I Need One Of These Unzip Programs? If you download a file that has an extension of RAR, ZIP, TAR, 7Z, and many other similar archive types, it's necessary to open the compressed file to find the files inside that you want to use. For the most part, when you download portable programs, a collections of photos, or any other group of files, all the data is held in one folder. But because you can't download a folder at once, the person giving out the files place them in a zipped up folder. You must unzip files from an archive file to use them. Here are some free programs that can unzip files. Each of these are free to use, and some even have portable download options so you can run the unzip program from a USB dive without installation.