Why has the ms-appinstaller protocol been disabled?

Rob Smiley 35 Reputation points
2023-12-15T13:36:49.5266667+00:00

We deploy our software in MSIX format and use the ms-appinstaller protocol to provide a one click install & configure link to our customers.

The link uses the documented format ms-appinstaller:?source=<download uri to msix>&activationUri=<configuration parameters>

This has been working well in Windows 10 22H1 and Windows 11.

The protocol appears to have been disabled without any announcement from Microsoft since 13th December 2023.

The app installer shows reason: "The ms-appinstaller protocol has been disabled. Please ask the vendor to update the weblink."

appinstaller

Why has this feature been disabled & when will it be restored?

Windows 10
Windows 10
A Microsoft operating system that runs on personal computers and tablets.
10,601 questions
Windows 11
Windows 11
A Microsoft operating system designed for productivity, creativity, and ease of use.
8,140 questions
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2 additional answers

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  1. Fabian König 0 Reputation points
    2023-12-22T11:45:33.38+00:00

    Fix when Microsoft pls. At least a statement...

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  2. INTREPID 31 Reputation points
    2023-12-29T18:10:46.0866667+00:00

    "Note: (not recommended) Customers that must use the ms-appinstaller protocol can still use the App Installer by setting the Group Policy Enable MSAppInstallerProtocol to ENABLED."
    You will need to download and install the group policy here:
    https://download.microsoft.com/download/d/3/5/d35c060c-d402-4a9c-ad40-234ad5e4d2e8/DesktopAppInstallerPolicies.zip
    See: https://www.bleepingcomputer.com/news/security/microsoft-now-lets-you-enable-the-windows-app-installer-again-heres-how/

    This is an apparently older policy that MS claims is the current one, but it's missing the MSAppInstallerProtocol (Microsoft Mistake...?):
    https://www.microsoft.com/en-us/download/details.aspx?id=103034

    Finally, also Critical TYPO on this page: https://msrc.microsoft.com/blog/2023/12/microsoft-addresses-app-installer-abuse/

    TYPO / ERROR: "Note: (not recommended) Customers that must use the ms-appinstaller protocol can still use the App Installer by setting the Group Policy EnableMSAppInstallerProtocol to Disabled."

    REQUIRED CORRECTION: "Note: (not recommended) Customers that must use the ms-appinstaller protocol can still use the App Installer by setting the Group Policy EnableMSAppInstallerProtocol to ENABLED."

    I reported the errors to Microsoft.

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