Unzip files on your PC

What unzipping does, and where the files go

A ZIP is one file holding many, usually compressed. Unzipping writes them back out as normal files and folders. Until you do, programs see only the ZIP: a Word document inside it opens read-only at best, and an installer may not run at all.

Octoolo puts the files in a new folder named after the ZIP, next to it, so Photos.zip becomes a Photos folder. When everything in the ZIP already sits inside one folder, that folder comes out as it is, without a second folder around it. If a folder by that name is already there, the new one is called Photos (2), so nothing is mixed up.

Extracting into a folder that already holds files with the same names? Octoolo counts them first and asks: Keep both (the new ones get a number), Replace or Skip.

Unzip from File Explorer's menu

Right-click a ZIP in File Explorer, choose Octoolo, then Extract here: the files go into a folder beside it, named as above, without a window to go through. A locked ZIP asks for its password first. Select several archives and each goes into its own folder. Open in Octoolo… shows the list of files instead, in a small Files window of its own.

On Windows 11 the Octoolo menu is under Show more options (or Shift+F10), because Windows 11's short menu only lists apps installed as signed packages. Octoolo is also in the ZIP's Open with list; what opens ZIPs on a double-click stays as you set it.

Opening one file without unzipping everything

Double-click a file in the list, or select it and press Open, and it opens in the app Windows uses for it: a PDF in your PDF reader, a photo in Photos. Octoolo takes out just that file into a temporary folder and clears those copies after a day. Changes you make to it are not saved back into the ZIP.

Programs and scripts (.exe, .msi, .bat, .ps1, .js, .vbs and the like) and Office files with macros never open on a double-click alone: Octoolo asks first, because files like these in a ZIP from the internet are a common way for harmful software to get in.

ZIPs Windows cannot open on its own

• AES passwords. File Explorer opens ZIPs locked the old way (ZipCrypto) but not those locked with AES, which 7-Zip and WinZip make. Octoolo opens both.
• Other compression methods. Besides the usual Deflate, Octoolo unpacks Deflate64, BZip2, LZMA, XZ, PPMd and Zstandard, and even Shrink, Reduce and Implode from 1990s PKZIP.
• Names in other languages. ZIPs made on older PCs store names in that PC's code page. Octoolo reads them as UTF-8 when they are, and otherwise as your PC's own code page, the way Windows does.

One thing it cannot open yet: a ZIP split into .z01, .z02 parts. A ZIP cut into .001, .002 pieces opens fine.