WinRAR is an archive manager with support for packing RAR and ZIP archives and unpacking RAR, ZIP, ZIP64, 7Z (7-Zip), CAB, ARJ, LZH (Lempel-Ziv-Huffman), TAR, GZ, ACE, UUE, BZ2, JAR (Java Archive developed by Sun Microsystems) and ISO (ISO9660) archives. You may use it to backup your data, reduce the size of email attachments, decompress files downloaded from the Internet and create your own file archives.

WinRAR features:

* WinRAR introduces an original compression algorithm.  It allows higher compression ratios than other PC archiving tools, especially for executable files, object libraries, large text files, etc.
* WinRAR offers an optional compression algorithm highly optimized for multimedia data.
* WinRAR supports files and archives up to 9,223,372,036,854,775,807 bytes in size, about 9000PB.  The number of archived files is unlimited for all practical purposes.
* WinRAR provides complete support for RAR and ZIP 2.0 archives and is able to unpack CAB, ARJ, LZH, TAR, GZ, ACE, UUE, BZ2, JAR, ISO, Z, 7Z archives.
* WinRAR supports NTFS file security and data streams.
* WinRAR offers both a classic interactive Windows interface and the command line interface.
* WinRAR provides functionality for creating a 'solid' archive, which can raise the compression ratio by 10% - 50% over more common methods, particularly when packing large numbers of small files.
* WinRAR offers the ability to create and change SFX archives using default and external SFX modules.
* WinRAR offers the ability to create a multi-volume archive as SFX.
* WinRAR offers a number of service functions, such as setting a password, adding archive and file comments.  Even physically damaged archives may be repaired and an archive may be locked to prevent further changes.  Authenticity information may be added for additional security and WinRAR will store information on the last update and name of the archive.

Bugs corrected in Version 3.70 beta 8:

- WinRAR shell extension did not work in Windows NT 4.0;
- when unpacking ZIP archives in command line mode WinRAR returned "write error" (numeric 5) code in situations when it should return "create error" (numeric 9).