Sometimes when compressing files into ZIP or RAR format, something goes wrong and the files compress incompletely. Although it is possible to open an incomplete ZIP or RAR file, to do so requires the use of a software utility as a helper. The only way to extract, or open, an incomplete file is if it is not corrupted. If the files are corrupted, you cannot open them.
ZIP and RAR files are not compatible and are not the same. They are completely different types of archive files and use different compression methods. This means one is not interchangeable with the other. However, some utilities do open both file types. When downloading a utility for a specific file extraction, make sure the utility can handle the file type you want to extract. Be warned that even though a utility opens incomplete files, it does not repair them.
According to the RARLab.com website, RAR files are the native formatting of the WinRAR archive utility. The WinRAR archive utility compresses many files into one smaller RAR file. Most people use RAR files to transport large amounts of data more easily. They are easier to e-mail and upload to the Internet. To extract a RAR file, use a special UnRAR utility, or an extractor, such as WinRAR, the original utility, or by using the ExtractNow utility, a free one from ExtractNow.com. The native compression utility will open an incomplete file, but the process is highly technical and requires the knowledge of command line instructions. Consult an IT professional if you decide to use this utility because entering the wrong command will cause system failure.
A ZIP file is an “interoperable file storage and transfer format,” according to the .ZIP File Format Specification APNOTE, released September 28, 2007. This is another compressed file format, much like the RAR file. The utility used to create a ZIP file compresses many files into one smaller ZIP file. This makes it easier to transport through e-mail. These files are also suitable for uploading numerous files to the Internet through one single ZIP file. To extract, or open, a ZIP file, use an unZIP utility, or an extractor, such as WinZIP or 7ZIP, a free utility from 7ZIP.org. The unZIP utility will open incomplete files, but consult an IT professional for help. The process requires using the command line utility, which is an open door to the operating system. The wrong command will cause system failure.
The ExtractNow utility has the capability to open or extract incomplete RAR and ZIP files without the use of the command line utility. This program is safe to use without the help of an IT professional. Download this utility from ExtractNow.com and save it to the desktop. Double-click on the set-up icon that looks like a floppy disk and labelled “extractnow” to run the program. Click “Run” when the box opens asking if you trust the program. The ExtractNow Setup Wizard runs. Install the program following the prompts. When finished, click the “Finish” button and the program opens automatically. Drag the RAR or ZIP file you want to open into the blank window of the utility. Click “Extract” and follow the prompts telling the program where to extract the file. When finished, the progress bar turns green and alerts you it is finished. Go to the folder where you directed the program to extract the files and open it as usual.