Blazor app crashes when debugging after windows secutiry updates

Rossend Bruch 255

Afert 2023 march 14 updates my app stop debugging. If I start it without debugging it works ok, if I start it debugging it crashes at startup. The error is the following:

Microsoft.WebAssembly.Diagnostics.DevToolsProxy[0] DevToolsProxy::Run: Exception System.AggregateException: One or more errors occurred. (Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')) ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index') at System.Collections.Generic.List1.get_Item(Int32 index) at Newtonsoft.Json.Linq.JContainer.GetItem(Int32 index) at Newtonsoft.Json.Linq.JArray.get_Item(Object key) at Microsoft.WebAssembly.Diagnostics.MonoProxy.AcceptEvent(SessionId sessionId, String method, JObject args, CancellationToken token) at Microsoft.WebAssembly.Diagnostics.DevToolsProxy.OnEvent(SessionId sessionId, String method, JObject args, CancellationToken token) --- End of inner exception stack trace --- at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions) at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task`1.get_Result() at Microsoft.WebAssembly.Diagnostics.DevToolsProxy.Run(Uri browserUri, WebSocket ideSocket)

Randy Mangar 45 Reputation points

2023-03-15T11:46:26.4+00:00

Exact same thing started happening to me this morning. I have tried VS 2022 17.4.4, 17.5.0, and 17.5.2.

If I don't have any breakpoints when starting up, it will run, but if I put a breakpoint during runtime, the app becomes very prone to crashing and closing again.

It seems to not happen to my colleague who is still on Windows 10 21H2.

Switching to Edge doesn't work.

What's the KBxxxxxxx number of the update that broke it for you?
Shivam Panchal 0 Reputation points

2023-03-15T12:14:15.7933333+00:00

Having this same issue
Matias Arrillaga 30 Reputation points

2023-03-15T12:54:44.05+00:00

i had the same issue. I discover than if i remove the interruption points, the application run.
Petra Stručić 0 Reputation points

2023-03-15T13:04:49.46+00:00

Don't know the solution but it's working for us if we switch to Edge instead of Chrome
Cade Brownlee 40 Reputation points

2023-03-15T13:53:04.21+00:00

I was having this same issue. Anytime I would run the program with breakpoints in my code it would crash.

Removing all breakpoints before running seems to work as a temporary fix for me
MD K 5 Reputation points

2023-03-15T15:06:17.4+00:00

I am having the same problem I thought I did something wrong but it seems like that not the case, I can run other blazor WASM project on debug mode but there is that one project wont run in debug mode but it runs fine if i run it without debug

The program '' has exited with code 4294967295 (0xffffffff).

The thread 0x0 has exited with code 0 (0x0).

The program 'localhost:7367' has exited with code 4294967295 (0xffffffff).

The program '[1248] ProjectName.Server.exe' has exited with code 4294967295 (0xffffffff).
Fredrik Lindqvist 0 Reputation points

2023-03-15T15:50:52.6233333+00:00

Same issue, after just upgrading Edge to 111.0.1661.41 both Edge and chrome has this behaviour. Deleting breakpoints works.
Ramsey, Tyler 10 Reputation points

2023-03-15T16:18:05.8066667+00:00

We are receiving the same error with .NET Blazor Web Assembly 6.0.15. Also confirmed that deleting breakpoints resolves the error.
Zackary Lowery 0 Reputation points

2023-03-15T16:23:02.01+00:00

I just wanted to confirm that I'm also seeing this issue.
Alex Hoyt 0 Reputation points

2023-03-15T16:27:31.0933333+00:00

Having the same issue. Removing all breakpoints when the app builds worked for me but its really annoying
Terence Hosken 0 Reputation points

2023-03-15T16:45:54.7733333+00:00

I'm having the same issue. App runs when I delete all breakpoints, not otherwise.
MusixTX 5 Reputation points

2023-03-15T17:50:46.16+00:00

I am somewhat relieved that it is probably not my program.

I just don't understand why a newly created project works anyway.

Firefox works by the way, but can't be debugged either. But at least it does not crash...
Alex Bulbazavr 20 Reputation points

2023-03-15T18:19:41.6833333+00:00

Downgrading the browser to prev version helps
Philip Keefer 1 Reputation point

2023-03-15T18:43:20.1233333+00:00

I too am having the exact same issue. Starting in debug mode with any breakpoints causes crash. Starting first and then adding breakpoints works, but is very annoying.
Austin Hodson 0 Reputation points

2023-03-15T18:46:50.9033333+00:00
I'm having this exact same issue.

As some others have already stated, If I don't have any breakpoints set when running the project, it runs fine. If I have any breakpoints set before running, it will crash immediately on start up.

If I set any breakpoints after it successfully starts, they will work for a while and then stop working inexplicably.

This same behavior happens in both Chrome and Edge. If I use Firefox, the project runs but it fails to load symbols for the breakpoints.

My colleague who is not experiencing this issue is running on a different OS build to me.

Colleague's Windows specifications:

Version: 21H2

OS Build: 19044.2604

My Windows Specifications:

Version: 21H2

OS Build: 19044.2728
Peter Galbraith 0 Reputation points

2023-03-15T18:47:06.0866667+00:00

Same issue. Wondering if Chromium is involved somehow. Chrome broke first, then Brave was working, it broke for me 12 hours later and then Edge was still working, now Edge is now broken. I looked at the modified dates on the applications and they all seem to be going through an auto-update.

Not sure its the cause, but it is weird that even after the windows updates, I still had some browser working and then they each failed over a 24 hour period.
Carl Blanchard 1 Reputation point

2023-03-15T19:49:36.22+00:00

I am having exact same issue, everything was working perfectly over the weekend, I updated Visual Studio to 17.5.1 - On Monday I could no longer debug my Blazor application. It looks like it errors when redirecting to auth server. I have managed to obtain the following error from Console.

I've tried rolling back and uninstalling, working on different branches. Visual Studio. everything!!!

I am still running on .net 6 with most Nuget packages @ 6.0.15 I don't really want to upgrade to .net 7 as it's not LTS.

fail: Microsoft.WebAssembly.Diagnostics.DevToolsProxy[0] DevToolsProxy::Run: Exception System.AggregateException: One or more errors occurred. (Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')) ---> System.ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index') at System.Collections.Generic.List1.get_Item(Int32 index) at Newtonsoft.Json.Linq.JContainer.GetItem(Int32 index) at Newtonsoft.Json.Linq.JArray.get_Item(Object key) at Microsoft.WebAssembly.Diagnostics.MonoProxy.AcceptEvent(SessionId sessionId, String method, JObject args, CancellationToken token) at Microsoft.WebAssembly.Diagnostics.DevToolsProxy.OnEvent(SessionId sessionId, String method, JObject args, CancellationToken token) --- End of inner exception stack trace --- at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions) at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification) at System.Threading.Tasks.Task`1.get_Result() at Microsoft.WebAssembly.Diagnostics.DevToolsProxy.Run(Uri browserUri, WebSocket ideSocket)
Sam Atwood 0 Reputation points

2023-03-15T20:00:55.33+00:00

We're having the same issue at our office. Making development on our flagship product nearly impossible. Hoping for a quick fix.
Isaac Borrero 0 Reputation points

2023-03-15T20:08:30.1533333+00:00

Having the same problem. Thought is was something different, then removed breakpoints, which fixed the problem, telling me I am experiencing the same problem.
Alan Muller 0 Reputation points

2023-03-15T21:21:01.01+00:00

Having this same issue
Cleiton Paiva Costa Marques 0 Reputation points

2023-03-15T21:29:15.32+00:00

I was looking for solutions and I didn't find it, until I got here and saw that I'm not the only one
chg 0 Reputation points

2023-03-15T21:48:27.3066667+00:00

Same issue. Cannot start the app with chrome, but works when switching to edge.
Daniel Roth 15 Reputation points Microsoft Employee

2023-03-16T04:15:51.8466667+00:00

This may be due to a recent Chrome regression. We are tracking the issue on the .NET & Blazor side at https://github.com/dotnet/runtime/issues/83452. Fixes are in the process of being deployed both from Chrome and a compensating fix in our debugging tools.
Ryan Waddell 5 Reputation points

2023-03-16T11:17:33.4633333+00:00

Just downloaded the latest version of Edge this morning (111.0.1661.43) and it looks like things are working again
Anthony Griggs 0 Reputation points

2023-03-16T12:39:28.43+00:00

Just a heads up, if you need help finding all of your breakpoints like I did. Hold the keys [Ctrl] + [Alt] +B down to bring up the Breakpoint Manager.
Cyril Portet 5 Reputation points

2023-03-16T16:02:52.73+00:00

Same issue here.

It works if i delete all breakpoints... In both debug or release.

It also works when using Firefox, even if i have some breakpoints defined.

So it's seems to be related to Chromium.

[Edit]

Just had an update from Edge (111.0.1661.43) and now... It works with Edge, even if i add breakpoints before debug !
Double 0 Reputation points

2023-03-16T17:43:37.14+00:00

Have this issue with chromium v.111 In both edge and chrome. Current workaround is using another chrome version. Downgrade or use beta Channel of chromium
Jason Wood 0 Reputation points

2023-03-17T05:43:18.5533333+00:00

I was having the same issue. Debugging a blazor wasm would immediately stop after edge loaded. Prior to yesterday, this has been working for years. Removing all the break points would "fix" the issue and I could add break points once it was running. I just updated Edge to version 111.0.1661.44 and I can once again debug with break points already set!
Erik Nakamura 0 Reputation points

2023-03-17T10:58:14.7366667+00:00

I am also having the same issue and I was only able to run following the above guidance to disable all breakpoints before starting visual studio
Pramod Pandav 5 Reputation points

2023-03-17T14:36:41.59+00:00

In my case, Now it's working after Updating the Visual Studio latest version 17.5.2
Brett Butcher 0 Reputation points

2023-03-20T11:22:30.27+00:00

I have had this issue too.. took me ages to realise because I unfortunately thought it was to do with updating VS. Wasted best part of a day trying to understand the problem.

I did find that if I simply disabled all the breakpoints I could then re-enable them as needed.
Pier Castonguay 0 Reputation points

2025-02-25T00:53:31.9633333+00:00

Still having this issue 2 years later. Latest Visual Studio version, Windows 11, NET9. Chrome and Edge do the same thing.

As soon as my Blazor app hit a breakpoint that was set before the project started, it crash and reload the page.

« JavaScript debug adapter' has exited with code 4294967295 (0xffffffff).

Accepted answer

Eren Özdemir 120 Reputation points

2023-03-16T07:50:53.73+00:00

I am able to use breakpoints if I add them after running the project.
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9 people found this answer helpful.
Rossend Bruch 255 Reputation points

2023-03-16T09:23:47.3366667+00:00

It is a chrominum issue. Las update breaks the solution when starting a debug session with breakpoints. Adding them after run works.

dc 0 Reputation points

2023-03-17T23:08:01.81+00:00

That's OK (well the whole situation is terrible) but if the page is reloaded it crashes so not suitable for debugging on load events.

Sandra Anderson 46 Reputation points

2023-03-17T23:15:15.68+00:00

Helpful to know but not efficient to work this way long term.

Jean Poulin 0 Reputation points

2023-03-21T00:49:35.9066667+00:00

Is this problem has been reported to Microsoft? The solution to add breakpoint after loading is worthless if I have to debug the loading page which is my case.

Does someone has a solution to debug loading page?
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Lance Wright 5 Reputation points

2023-03-23T22:53:31.1833333+00:00

So as of today, Edge and Chrome are working. Chrome version 111.0.5563.111. I imagine this was truly a Microsoft update that broke everything and the browsers had to make an update to follow up. Because seeing different browsers fix the issue after some updates is pretty telling as to what happened. I professionally work on Blazor Server and Blazor WebAssembly projects. Only WebAssembly was broke, but it broke literally everything. If you had any breakpoints before you launched the code, everything would crash with WebAssembly and this was a huge set back for my company as we were not aware that the breakpoints were the issue for the first day or two. Blazor Server never seemed to be part of this issue as it worked this whole time, which would make sense since it's server side and not really the same as WebAssembly.

So go update your browsers, I'm sure more than just Chrome and Edge is working now.
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Ali Poustdouzan 0 Reputation points

2023-03-17T11:37:02.0833333+00:00
After update my windows 11 in 2022-03-15 i have same issue, If i have any breakpoint in project my blazor app will crash after running in chrome and edge, But working in firefox.

Problem is firefox doesn't support debug for blazor.

Solution :

Delete all breakpoints

Run project in chrome or edge

After that add your breakpoint

UPDATE :
Debug work on edge after update edge to last version, But still not working in chrome.

I hope they fix this issue soon
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Pankit Patel 0 Reputation points

2023-03-17T12:11:52.2+00:00

I am also experiencing an issue where my Blazor webassembly application crashes when I try to debug it.
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Andrew 0 Reputation points

2023-03-17T16:24:16.11+00:00

This sucks, our company are paid enterprise VS users and we're all stuck with this.
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Blazor app crashes when debugging after windows secutiry updates

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