[UWP] Crash after Opt-in for Multiple Instances

Question

I have a UWP application project built with VS2017 15.7.3

the app targeting is:

Target version: Windows 10, version 1803 

Min version: Windows 10 Creators Update 

To opt-in for multiple instances support, 

1:

add desktop4:SupportsMultipleInstances="true" in "package.appxmanifest"

2: add conditional compilation symbol DISABLE_XAML_GENERATED_MAIN

and added a test Program.cs with the following code

static void Main(string[] args)
{

           
     var activatedArgs = AppInstance.GetActivatedEventArgs();
            
     Application.Start((p) => new App());
}

everything compiles correctly.

However the app crashes before it ever reaches Main.

From the event viewer, I got this error

Activation for 5d40a47e-385b-495e-9232-b715cf6fd008_4fddxyvsdr1hc!App failed. Error code: The app didn't start.. Activation phase: COM ActivateExtension

If I upgrade the min targeting version to be version 1803, everything seems fine.

Is the crash normal?

and 

how to opt-in multiple instances for my app on windows 10, 1803 runtime while staying compactible with lower windows 10 versions?

Answer 1

Hello,

Please read the sticky posts, especially the Guide to posting: subject line tags , and don't forget add tag to your question.

Why your min version is 1703. You are using features from 1803. Change min version to 1803 and all will work.

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Answer 2

That is min version is designed for, so a binary package could light up "new features" on newer version of Windows 10 while compatible with older ones.

Answer 3

 so a binary package could light up "new features" on newer version of Windows 10 while compatible with older ones.

But not for MultipleInstances and some other features  which is declared in Manifest file. 

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Answer 4

in another word, in order to use these new features, the binary must stop working on lower versions?

Could any staff from Microsoft please confirm this?

Answer 5

@hereafter,

See the doc here:

https://docs.microsoft.com/en-us/windows/uwp/debug-test-perf/version-adaptive-code

"You must increase your app's Minimum Version if you use:

a new API that requires a capability that isn't available in an earlier version. You must increase the minimum supported version to one that includes that capability. For more info, see App capability declarations."

Best regards,

Barry

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