A Mutable Log

Self-sign UWP appx or appxbundle for side-loading

Windows 10 apps built for side-loading are written to a directory with the _Test suffix, that also contains a PowerShell script called Install.ps1 to automate side-loading. This post shows how you can side-load an as yet unsigned appx or appxbundle.

First, you’ll need to create a self-signed certificate for package signing.

In PowerShell, run

New-SelfSignedCertificate -Type Custom -Subject "CN=MyCompany" -KeyUsage DigitalSignature -FriendlyName "MyCompany Test Cert" -CertStoreLocation "Cert:\CurrentUser\My" -TextExtension @("2.5.29.37={text}1.3.6.1.5.5.7.3.3", "2.5.29.19={text}")

Open developer command prompt of Visual Studio and run

SignTool sign /fd sha256 /a /n MyCompany MyApp_x86.appxbundle

Use /p option to specify password if needed.

Note that Subject should match Publisher attribute of Identity element in Package.appxmanifest or AppxManifest.xml, or signing will fail with

SignTool Error: An unexpected internal error has occurred.
Error information: "Error: SignerSign() failed." (-2147024885/0x8007000b)

Now, you can run Install.ps1 to side-load the app. If side-loading fails, you’ve probably not enabled it in Settings.