Ok, this one has been driving me nuts for a couple of weeks now, ever since I rebuilt my system and installed Windows 7 64-bit. I have been using 7-zip for years, and kept on using it long after Windows gained excellent in-shell support for .ZIP folders, because 7-zip handles RAR, TAR and other formats, and unlike WinRAR it’s free and open source. However, after installing it on the 64-bit edition of Windows 7 I consistently got an “Incorrect Command Line” error trying to open RAR archives by double-clicking them in Explorer. If I right-clicked the archive and selected 7-zip -> Open Archive it worked fine. Not a big deal, but I’m the kind of guy to be bothered by this stuff until I get it fixed.
Today I noticed something interesting. If I right-clicked the file and chose Open With -> 7-zip GUI, I got the same error. However if I right-clicked and chose Open With -> 7-zip File Manager it worked fine, and got me to the archive folder view I wanted. For those of you not familiar with the different versions of 7-zip that come in the default install, there are three: 7-zip Console, 7-zip GUI, and 7-zip File Manager. Now I don’t understand exactly how 7-zip GUI differs from File Manager, but I’ll go out on a limb and assume it’s a GUI view of a single archive, rather than an Explorer-like Window in which you can navigate to different folders. Whatever. All that matters to me is that when I went into Control Panel -> Default Programs -> Associate a file type or protocol with a program, selected the .rar file extension, and clicked Change Program I was able to choose 7-zip File Manager as the default, and from that point onward it worked as it should. Tada!