.MSIX

How to Open an MSIX File

An .msix file is Microsoft's modern Windows app package format — the successor to both the classic EXE/MSI installer and the older APPX format. It installs with one double-click on Windows, but it's structurally just a signed ZIP archive, so its real identity, permissions and signature status can be read directly — without installing anything.

Written & tested by the File-Extension.com team — see our testing methodology.

Category: App installer package Developer: Microsoft MIME type: application/msix Native support: Windows 10/11 only

Open an MSIX File Online

Drop an .msix file below. It's a signed ZIP archive under the hood, so this tool reads its real AppxManifest.xml directly — the app's declared name, publisher, version, target devices and every capability (permission) it asks for — plus whether an AppxSignature.p7x is present, all without installing the package or extracting a single file to disk.

🔒 Nothing is uploaded — your file never leaves this device

On this page

  1. Open an MSIX file online (tool)
  2. Quick answer
  3. What is an MSIX file?
  4. Install on Windows
  5. Open on Mac or Linux
  6. Common problems & fixes
  7. Related file extensions
  8. Technical references
  9. FAQ
Fastest answer: On Windows 10 or 11, just double-click the .msix file — the built-in App Installer opens and shows the app's details before you click Install. MSIX is Windows-only, so on Mac or Linux you can only inspect its contents (it's a ZIP archive), not run the app. Use the tool above first if you want to see what the package actually declares before installing it.

What is an MSIX file?

MSIX is Microsoft's modern app-packaging format for Windows, introduced to replace the older mix of MSI installers, ClickOnce, App-V and the earlier APPX format with one consistent, more secure package type. Every MSIX app is digitally signed, installs cleanly with full uninstall support, and runs with a declared, sandboxed set of capabilities (permissions) — similar in spirit to how mobile app stores work.

Structurally, an .msix file is just a ZIP archive containing a required AppxManifest.xml (the app's identity, dependencies and declared capabilities), an AppxBlockMap.xml (a hash map used to verify each file during installation), a [Content_Types].xml, the app's own payload files, and — for any package meant to actually install — an AppxSignature.p7x digital signature. That's exactly the structure this page's tool reads directly, without installing or extracting anything.

How to install an MSIX file on Windows

  1. Double-click the .msix file. Windows 10/11 opens the built-in App Installer, showing the app's name, publisher and permissions.
  2. Click Install. If the publisher's certificate isn't already trusted (common for apps not from the Microsoft Store), you may need to install that certificate first or enable sideloading.
  3. To enable sideloading of unsigned-by-store apps, go to Settings > Apps > Advanced app settings and set "Install apps" to allow apps from anywhere, or at least apps you sideload.
  4. Alternatively, install from an elevated PowerShell window with Add-AppxPackage -Path "C:\path\to\yourfile.msix", which gives clearer error messages than the graphical installer if something fails.
  5. Use the tool on this page first if the file is from an unfamiliar source, to see its declared identity, capabilities and signature status before installing.

How to open an MSIX file on Mac or Linux

  1. MSIX apps only run on Windows 10/11 — there's no way to install or launch one on Mac or Linux.
  2. Since an .msix is really a ZIP archive, you can rename the extension to .zip (or just point an archive tool at it directly) and extract it on any OS to inspect the files inside.
  3. Use the tool on this page to see the parsed AppxManifest.xml contents — app identity, capabilities, target devices — without needing to extract or rename anything.

Common MSIX file problems and how to fix them

"This app package is not signed with a trusted certificate"

MSIX requires every package to be signed, and Windows must trust that certificate. For apps not distributed through the Microsoft Store, you often need to manually install the publisher's certificate into the Trusted People or Trusted Root store first (right-click the certificate > Install Certificate), then try installing again.

"Add-AppxPackage failed because of the following error: The package could not be opened"

The file is often incomplete or corrupted. Re-download it and check its size against what the source lists, if given. Use the tool on this page first — if it can't find a valid End Of Central Directory record, the ZIP container itself is damaged.

Sideloading is blocked / "This app package's publisher requires Device Guard signing"

Enable sideloading under Settings > Apps > Advanced app settings, or check with your IT administrator if this is a managed/work device with sideloading policies enforced.

Technical references

MSIX is a Microsoft-defined packaging format, documented directly by Microsoft as part of the Windows developer documentation.

Frequently asked questions

What program opens an .msix file?

On Windows 10 or 11, double-clicking an .msix file opens the built-in App Installer, which shows the app's details and lets you install it directly — no separate program needed. MSIX isn't a Mac or Linux format.

Can I open an MSIX file on Mac or Linux?

Not to install and run it — MSIX apps are Windows-only. Since it's structurally a ZIP archive, you can rename the extension to .zip and extract it on any OS to inspect the files inside, including the AppxManifest.xml the tool on this page reads directly.

Why does Windows say it can't install my MSIX file?

The most common cause is a missing or untrusted signing certificate — MSIX packages must be digitally signed, and unless the publisher's certificate is trusted by your PC (or the app came through the Microsoft Store), Windows will refuse to install it. Sideloading also needs to be enabled in Windows Settings > Apps > Advanced app settings.

Is an MSIX file safe to open?

MSIX itself is Microsoft's modern, more secure app-packaging format — every package must be signed, and installed apps run in a lightweight sandbox with clearly declared capabilities. As with any installer, only install one from a publisher you trust, and check what capabilities (like access to your documents or webcam) it declares before installing.

Last updated September 21, 2026.