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.USTAR file extension

To open .USTAR files on Windows, try a tar-capable archiver (for example, 7-Zip or WinRAR) and use Extract to a folder.

To open a .USTAR file, treat it as a tar archive and extract it with a tar tool (for example, GNU tar or bsdtar). Avoid renaming the file extension; instead, open or extract it using tar-capable software.

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Last updated: June 10, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page
  • Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
  • Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
  • Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
  • Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
  • Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

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Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .USTAR files

Use these platform-specific instructions to open .USTAR files safely.

Windows

  1. Try a tar-capable archiver (for example, 7-Zip or WinRAR) and use Extract to a folder.
  2. If you have a tar tool available, run: tar -xf yourfile.ustar to extract its contents.
Full Windows guide

Mac

  1. Open Terminal and extract it with: tar -xf yourfile.ustar (choose a destination folder first if needed).
  2. If you prefer a GUI, use an archive utility that supports tar archives and extract the file.
Full Mac guide

Linux

  1. In a terminal, extract with GNU tar: tar -xf yourfile.ustar.
  2. Alternatively, use bsdtar (libarchive): bsdtar -xf yourfile.ustar.
Full Linux guide

iOS

  1. iOS may not reliably extract uncommon tar extensions; if the Files app can’t open it, transfer the .ustar file to a desktop system and extract it with tar/bsdtar.
Full iOS guide

Android

  1. Android support varies by file manager; if it won’t open, move the .ustar file to a desktop system and extract it with a tar-capable tool.
Full Android guide

Security notes

  • Be cautious when extracting archives from untrusted sources: tar/ustar archives can contain executable files or scripts that are harmless until you run them, but could be malicious if executed.
  • Watch for unsafe paths during extraction (for example, entries that try to write outside the target folder using absolute paths or “../” traversal). Extract into a new, empty directory and verify where files land before moving them.
  • Archive parsing is complex; if a tool crashes or behaves oddly when opening a .ustar, switch to a well-maintained tar implementation (for example, GNU tar or libarchive/bsdtar) and keep it updated.

What can hide inside an archive

Compressed packages can contain executables or scripts you only see after extraction. Double extensions and nested archives are common tricks. Scan unexpected downloads before unpacking, and extract to an empty folder so you can review contents safely.

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Can't open this file?

These are the most common causes and fixes when .USTAR files fail to open.

Common reasons

  • The .USTAR file won’t open in my archive app
  • Extraction fails or reports a corrupted archive
  • Files extract but names/paths look wrong
  • After extracting, I’m not sure what to open

Fix steps

  1. Open it explicitly as a tar archive in a tar-capable tool, or use command-line extraction (tar -xf).
  2. If your app only keys off extensions, keep the file content unchanged and try opening it via the app’s File > Open dialog (rather than double-clicking).

OS-specific troubleshooting

What is a .USTAR file?

.USTAR typically denotes a tar archive written in the POSIX.1-1988 “ustar” format (Unix Standard TAR). It’s a standardized tar variant with defined header fields and broad compatibility across Unix-like systems and tools. Many tar implementations can read/write ustar, and modern tools may also support related tar variants such as pax extensions.

Background

USTAR (Unix Standard TAR) is the first official tar standard (POSIX 1988). In practice, a “.ustar” file is simply a tar archive that indicates it uses the ustar header layout, which improved portability compared to older tar layouts.

Common MIME types: application/x-ustar

Further reading

Authoritative resources for more details on the .USTAR format.

Common .USTAR issues

The .USTAR file won’t open in my archive app

Some apps only recognize common extensions like .tar, or they don’t support tar/ustar well even if they support ZIP/RAR.

  1. Open it explicitly as a tar archive in a tar-capable tool, or use command-line extraction (tar -xf).
  2. If your app only keys off extensions, keep the file content unchanged and try opening it via the app’s File > Open dialog (rather than double-clicking).

Extraction fails or reports a corrupted archive

The download may be incomplete, or the archive may use features your tool doesn’t handle well.

  1. Re-download or re-copy the file and try extraction again.
  2. Try a different implementation (GNU tar vs bsdtar/libarchive) to see if one handles the archive better.

Files extract but names/paths look wrong

Tar archives can contain long paths, special entries, or metadata that different tar readers interpret differently (including ustar vs newer tar variants such as pax).

  1. Try extracting with a different tar tool (GNU tar or bsdtar) and compare results.
  2. Extract into an empty folder and review the resulting directory structure before moving files into important locations.

After extracting, I’m not sure what to open

USTAR is just a container; the real file types are inside it.

  1. Inspect the extracted files and open them based on their actual extensions and content.
  2. If there’s no extension, use your OS file information tools or open with a text editor to identify the content safely.

FAQ

Is .USTAR the same as .TAR?

It’s a tar archive, typically specifically written using the POSIX “ustar” tar format. Many tools treat it like a normal tar file, but “ustar” refers to a particular standardized header layout.

Can I convert .USTAR to .ZIP?

Yes, by extracting the .ustar first and then creating a new ZIP from the extracted files. Renaming the extension does not convert the archive format.

Does .USTAR support compression (like .tar.gz)?

USTAR describes the tar archive format itself, not compression. If you want compression, it’s typically done by compressing the tar file (for example, creating a gzip-compressed tar in a separate step).

Which tools can create or read ustar archives?

Common tar tools can handle ustar; GNU tar documents the ustar format, and libarchive tools (such as bsdtar) can create archives in “ustar” format.

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