What is a XZ file?
XZ — maximum compression
Use the format XZ
A concrete example
Decompress a .tar.xz to access the TAR package.
Useful checks
Check the expected content and available space after decompression. The compressed size may be much smaller than the extracted size.
Choose a conversion
Keep the original and open the result in the software or on the device that will need to use it.
Your questions about this format
Why did I receive a TAR.GZ file?
Gzip compresses a stream, while TAR groups the files of a folder. The engine therefore combines the two to preserve the contents of a multi-part archive. Open the TAR.GZ with compatible software, then check the extracted files.
Does converting an archive change the documents inside?
The goal is to change their container, not to convert each document. A PDF in an archive remains a PDF. To change its format, extract it and then use the Documents theme.
Will a ZIP archive necessarily be smaller?
No. JPEG photos, videos, or already compressed archives may shrink very little. Compare the size and prioritize especially the format that your recipient knows how to open.
What to do with a protected or damaged archive?
The form does not ask for a password. Unlock your archive locally if you are allowed to, then try again with a copy. If it is damaged, first check that your local software can extract the files; paying does not repair an unreadable archive.
What is it?
XZ delivers the best compression ratio among the classic Unix formats, relying on the same algorithm as 7Z.
It is slow to compress but fast to decompress — a trade-off perfectly suited to software distribution: you compress once and decompress millions of times.
History & origin
XZ appeared in 2009 and quickly established itself as the standard format for distributing Linux source code, including the kernel itself.
It made headlines in 2024: a backdoor had been patiently inserted, over several years, into the tool that produces these archives. Discovered by chance, it targeted servers worldwide — one of the most sophisticated attack attempts ever observed in open-source software.
Why it is useful
The best compression ratio in the Unix world, paired with fast decompression.
An open, standardized format.
Limits & drawbacks
Compression is very slow and memory-intensive.
Like its relatives, it only handles a single file: TAR is still needed to archive a folder.
Practical tips
To share a .xz or .tar.xz file with someone on Windows, convert it to ZIP.
XZ works best for archiving large volumes of data that you'll decompress often but never recompress.
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Convert a XZ