Formats
Zip, 7z, self-extracting and signed archives
New in 1.9.12, and free for everyone: MCZ also writes standard .zip and .7z files for
people without MCZ, makes archives that unpack themselves, and signs archives so the people you send them to know they
came from you, unchanged. An .mcz archive is still the default: it is smaller and faster.
Save as zip
Choose Zip (opens anywhere) in the Compress tab's format list, right-click a file or folder in Explorer
or Ubuntu Files and choose Compress to Zip, or run mcz zip, for a standard
.zip that Windows Explorer, macOS and every unzip tool open. MCZ compresses it on every core, stores
files that would not shrink, keeps names and file times, and switches to Zip64 past 4 GB or 65,535 files.
Save as 7z
Choose 7z (7-Zip compatible), right-click a file or folder and choose Compress to 7z,
or run mcz 7z, for a .7z that 7-Zip,
NanaZip, Windows 11 and p7zip open. Levels 0 to 9 like 7-Zip's (default 5), compressed on every core. Smaller than
a zip.
Convert to MCZ
Right-click a .zip or .7z in Explorer or Ubuntu Files, use Convert a zip or 7z to
MCZ... on the Compress tab, or run mcz convert, to get a .mcz of the same name
beside it. The original is kept. Files that use Deflate64, as some zips from Windows Explorer and 7-Zip do, convert
too. Password-protected files and rare methods are refused with a message.
Convert MCZ to zip or 7z
New in 1.9.14. Right-click a .mcz and choose Convert to Zip or Convert to 7z,
use Convert MCZ to zip or 7z... on the Compress tab, or run
mcz convert archive.mcz out.zip, to get a standard file for people without MCZ. The .mcz is
kept. A signed archive loses its signature: zip and 7z files cannot carry one, so MCZ warns you first.
Self-extracting archives
Choose Self-extracting (.exe) (.run on Linux), or run
mcz c Photos.exe <files> --sfx, for one program that unpacks itself on a PC without MCZ, on every
core and with every file checked. On Windows a double-click shows a small window to pick the folder; on Linux
./Photos.run extracts beside it. mcz sfx turns an existing archive into one.
Signed archives
Make a key once (Keys... next to Sign with, or mcz key new) and sign
the archives you make. People who trust your public key see who signed an archive when they extract or verify it,
and MCZ stops before writing anything if the signature is invalid. --require-signed refuses anything
unsigned.
For AI assistants too
The MCP server has new tools mcz_zip, mcz_7z, mcz_convert and
mcz_sfx, all usable without a premium key. See the AI page.
Good to know
- Self-extracting programs are not code-signed yet, so Windows may first say they are from an unknown publisher. The program is the archive plus about 0.4 MB on Windows, 1 MB on Linux.
- An archive signature proves who made it and that nothing changed; it is separate from Windows code signing. Only
.mczarchives carry it: send the.mczitself when the signature matters. - Zip and 7z files are larger and slower to make than
.mczarchives. Use them when the other side does not have MCZ.
Full details, with every command and switch, are in the user manual on the Download page (sections 4.8 to 4.12).