[Bug] macOS version not supported when attempting to start default browser after upgrading to .net 10

[johnsoukka]

Library version used

4.76.0

.NET version

.net 10

Scenario

Other - please specify

Is this a new or an existing app?

None

Issue description and reproduction steps

After upgrading my .net core web application from .net 8 to .net10 I get this issue when attempting to authenticate to my SQL Server database with active directory interactive.

Microsoft.Data.SqlClient.SqlException (0x80131904): macOS 15.7.1
       ---> System.PlatformNotSupportedException: macOS 15.7.1
         at Microsoft.Identity.Client.Platforms.netstandard.NetCorePlatformProxy.StartDefaultOsBrowserAsync(String url, Boolean isBrokerConfigured)

It works fine on .net 8.

If I run dotnet nuget why [myproject] Microsoft.Identity.Client I can see that the version being used is 4.76.0 disregarding if I switch between .net 8 or .net 10.

To reproduce with a new project follow these steps on MacOS:

dotnet new console --name TestMsal -f net10.0
cd TestMsal
dotnet add package Microsoft.Data.SqlClient

Add this code in Program.cs

// See https://aka.ms/new-console-template for more information
Console.WriteLine("Hello, World!");

using var connection = new Microsoft.Data.SqlClient.SqlConnection("server=myserver;database=mydb;Authentication=Active Directory Interactive;Encrypt=True;TrustServerCertificate=True");
connection.Open();
using var command = new Microsoft.Data.SqlClient.SqlCommand("SELECT 1", connection);
var result = await command.ExecuteScalarAsync();
Console.WriteLine($"Query Result: {result}");

Run it:

dotnet run

I see the exception on my MacOS.

You can then switch target framework to net8.0 in your TestMsal.csproj.
Run it:
dotnet run

Authenticate and the application will succeed and we will see Query Result: 1 printed.

It should be noted that when reproducing with a complete new app the version being used (as of today) is 4.73.1 although my version in my real application where I have the issue is 4.76.0 as reported.

Exactly the same behaviour though.

I was unsure how to answer: Are you using PublicClientApplication, ConfidentialClientApplication or ManagedIdentityApplication?
Hence I left the answer as "other". I'm certainly using one of the other alternatives, not sure which though.

Relevant code snippets

Expected behavior

Expect it to work in the same way as for .net 8. A browser is opened so that I can authenticate.

Identity provider

Microsoft Entra ID (Work and School accounts and Personal Microsoft accounts)

Regression

No response

Solution and workarounds

Stay on .net 8.

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• [Bug] System.PlatformNotSupportedException when using AcquireTokenInteractive on macOS (Darwin 23.4.0, ARM64, M3 chip) #4890

---

Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Can you try to delete .WithUseEmbeddedWebView(false) - that's the default anyway.

Reference:

• [Bug] System.PlatformNotSupportedException when using AcquireTokenInteractive on macOS (Darwin 23.4.0, ARM64, M3 chip) #4890 (comment)

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[johnsoukka]

Here are some similar issues that might help you. Please check if they can solve your problem.

• [Bug] System.PlatformNotSupportedException when using AcquireTokenInteractive on macOS (Darwin 23.4.0, ARM64, M3 chip) #4890

Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Can you try to delete .WithUseEmbeddedWebView(false) - that's the default anyway.

Reference:

• [Bug] System.PlatformNotSupportedException when using AcquireTokenInteractive on macOS (Darwin 23.4.0, ARM64, M3 chip) #4890 (comment)

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Well. I am not configuring anything around the MSAL client. That sits within Microsoft.Data.SqlClient I suppose.
I felt this was the correct repo to report in but perhaps the bug is within that repo and their use of this library?

The fact that this works with one supported .net version and not the latest one indicates to me that it is a bug that has surfaced and likely needs to be fixed in in this code.

[johnsoukka]

Trying to dig inside the code a bit.

Found this inside DesktopOsHelper:

public static bool IsMac()
        {
#if __MOBILE__
            return false;
#elif NETFRAMEWORK
            return Environment.OSVersion.Platform == PlatformID.MacOSX;
#elif NET8_0_OR_GREATER
            string OSDescription = RuntimeInformation.OSDescription;
            return OSDescription.Contains("Darwin", StringComparison.OrdinalIgnoreCase);
#else
            return RuntimeInformation.IsOSPlatform(OSPlatform.OSX);
#endif
        }

If I change my simple console app to this:

var osDescription = System.Runtime.InteropServices.RuntimeInformation.OSDescription;
Console.WriteLine($"OS: {osDescription}");

For .net 8 the result is:
OS: Darwin 24.6.0 Darwin Kernel Version 24.6.0: Mon Aug...

For .net 10 the result is:
OS: macOS 15.7.1

It seems likely to be issue if I am searching in the correct area of the code.

Also worth mentioning RuntimeInformation.IsOSPlatform(OSPlatform.OSX) returns true for both .net versions.
I don't know the reasoning behind opting for string comparison rather than using this. Still worth to know that it could be a possible fix or possible temporary fix to let .net 10 fall into this else case.

[jrr]

For context, this issue prevents interactive auth from working at all on a Mac on .NET 10 (see linked sqlclient issue).

This open one-line PR should fix it. Can we get some attention on this please?

[cheenamalhotra]

@bgavrilMS seems like this is a potential blocker for .NET 10 and Entra ID Auth adoption, do you have a tentative timeline when this fix can be released in MSAL.NET and Azure.Identity subsequently?