FAQ - Frequently Asked Questions

Can I use 7Zip in a commercial organization?

Yes, 7Zip is free software. You can use it on any computer. You don't need to register or pay for 7Zip.

How can I set file associations to 7Zip in Windows 7 and Windows Vista?

You must run 7Zip File Manager in administrator mode. Right-click the icon of 7Zip File Manager, and then click Run as administrator. Then you can change file associations and some other options.

Why do the add, delete and update operations not work for some existing archives?

The current version of 7Zip can't execute some operations with .7z archives that have been created with the "solid" option switched on. You can disable solid mode with -ms=off switch in command line. Latest beta version of 7Zip supports any operations with "solid" archives.

Why can't 7Zip open some ZIP archives?

In 99% of these cases it means that the archive contains incorrect headers. Other ZIP programs can open some archives with incorrect headers, since these programs just ignore errors. If you have such archive, please don't call the 7-Zip developers about it. Instead try to find the program that was used to create the archive and inform the developers of that program that their software is not ZIP-compatible. There are also some ZIP archives that were encoded with methods unsupported by 7Zip, for example, WAVPack (WinZip).

What does the 7Zip download include?

The 7Zip download bundle includes the 7zip file compression application and a powerful video/search toolbar for your internet browser.

How can I install 7Zip in silent mode?

Use the "/S" parameter to do a silent installation and the "/D=dir" parameter to specify the "output directory". These options are case-sensitive. 7Zip uses the NSIS installer by Nullsoft.

Why doesn't the command line version add files without extensions to an archive?

You're probably using a *.* wildcard. 7Zip doesn't use the operating system's wildcard mask parser, and consequently treats *.* as any file that has an extension. To process all files you must use the * wildcard instead or omit the wildcard altogether.