Remote debugging of ASP.NET (.NET Core 8) app under IIS 10 will not show source code on breakpoint

Osborne,J,Jon,QDN R 0

Historically, I've had no problems using the remote debugger on a Windows server for .NET Framework web services. I've now had to create a .NET Core 8 Web API using VS2022. I've published the service to a W2016 host and am hosting it under IIS (10.0.14393.0) using a new AppPool with the "No Managed Code" CLR version. I can successfully start up the remote debugger with admin privs on a port that is accessible to my developement machine. The development machine is running VS2022. When I've loaded the solution, I can attach to the remote debugger and the relevant process. However, if I set a break point on a line of C# code in a controller, for example, and call the related API exposed on the W2016 IIS port, VS2022 does not jump to the line where the break point is active - it shows a tabbed window with "The applicaiton is in break mode" and presents three options of "Show Diagnostic Tools", "Check for running Tasks" and "Continue execution". Meanwhile, I can see that in the "Modules" windows that the symbols for my application are loaded as expected.

I've tried regressing from the very latest VS2022 to the previous version (17.12.2) but this happens in both versions.

I've tried creating a really simple Web API from the template that create the Weather forecast API for .NET Core 8 and hosting that, but it behaves in the same way.

I've deployed the latest .NET 8 Server Hosting bundle (8.0.11) and restarted afterwards.

I don't know what to try next. This article seems to imply that this should all be possible but wonder whether this is at all possible or not, but would have thought to have found an article that would have said if that was not possible - https://learn.microsoft.com/en-us/visualstudio/debugger/remote-debugging-aspnet-on-a-remote-iis-computer?view=vs-2022. The project was published using the "Debug" configuration; with the "net8.0" target framework and the "Portable" target runtime (but have also tried x64 too).

So am looking for any further suggestions on things to try, or to be told if this is simply not possible,

Brando Zhang-MSFT 3,791 Reputation points Microsoft Vendor

2024-12-19T01:40:01.5633333+00:00

Have you tried remote debug at other server or test it inside the local machine to see if this issue is still existed or not?
Osborne,J,Jon,QDN R 0 Reputation points

2024-12-19T13:24:10.64+00:00

So, firstly, locally debugging it is fine. I've used remote debug a lot with .NET Framework apps under IIS; Classic ASP sites under IIS but not yet had to deploy a .NET Core one. I do want to deploy this Web API under IIS for the benefit of being able to safely recycle AppPools rather than run it as a standalone Kestrel service. The server has the right .NET 8 runtimes deployed, as it runs fine, but having the ability to debug it will be very valuable and would either like to overcome this issue am having, or be told categorically that it's not possible to achieve this and pointed to some official Microsoft document that states that. However, at present, the Microsoft documation I reference in my original posting seems to imply it should be possible. It is partly in that I can connect to a running instance, set a break point in my code and it will stop but it won't tell me where it's stopped like it does in all other scenarios so the value of that is next to zero until I resolve this.
Brando Zhang-MSFT 3,791 Reputation points Microsoft Vendor

2024-12-20T03:02:11.9633333+00:00

I suggest you could recheck below things, firstly make sure the pdb file is inside the published folder. Secondly , I suggest you could check the Debug > Options > General, ensure:

Enable Just My Code is unchecked.

Enable .NET Core Debugging is enabled.

Use Managed Compatibility Mode is unchecked unless explicitly needed.
Osborne,J,Jon,QDN R 0 Reputation points

2024-12-20T13:01:26.8333333+00:00

Thanks for the suggestions. Can't find the last two options you mention, are they expressed differently in the user interface?

"Enable .NET Core Debugging is enabled.

Use Managed Compatibility Mode is unchecked unless explicitly needed."
Brando Zhang-MSFT 3,791 Reputation points Microsoft Vendor

2024-12-23T01:30:12.7833333+00:00

Sorry for misunderstanding, VS 2022 doesn't contain such option now, could you please tell me your VS version? enterprise, professional or else? Actually, it's hard to troubleshoot such kind of issue, I suggest you could consider create a support ticket for this to ask MSFT engineer have a remote session with you to troubleshoot, you could find the details at this link.
Osborne,J,Jon,QDN R 0 Reputation points

2024-12-23T08:54:02.3933333+00:00

VS2022 Professional 17.12.3Remote debugger 17.0.35506.110

Tried targetting .NET Core 8.011 and 6.0.36 with appropriate ASP bundle runtimes on W2016 Data center edition (1607 OS Build 14393.7515) using IIS 10.0.14393.0

Yeh - appreciate how hard these things can be to replicate at times, but tried this from two different VS2022 installations and the results are the same for me at present. Don't have another Windows OS version I could try, but could try on another server host instance shortly.
Brando Zhang-MSFT 3,791 Reputation points Microsoft Vendor

2024-12-25T07:32:36.47+00:00

Yes, I suggest you could try it with other server to see if this issue could be reproduced or note.

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Remote debugging of ASP.NET (.NET Core 8) app under IIS 10 will not show source code on breakpoint

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