Blazor WebAssembly Application fails to load due to integrity errors

The most likely reason why this is happening, is that some Antiviruses block the execution of downloaded .dll files. That's why it is working in some networks, but doesn't in some others.

What you can do, and what is also suggested as a Workaround by microsoft, is to rename all .dll to .bin - and also change the config json. it worked in my case.

I use the following PowerShell function for that:

Function Hide-BlazorDLL {

    Param(
        [string]$Path = (Get-Location).Path
    )

    <#
        According to the following Links:
        https://github.com/dotnet/aspnetcore/issues/19552
        https://github.com/dotnet/aspnetcore/issues/5477#issuecomment-599148931
        https://github.com/dotnet/aspnetcore/issues/21489
        https://gist.github.com/Swimburger/774ca2b63bad4a16eb2fa23b47297e71 
    #>

    # Test if path is correct and accessible
    $WorkingDir = Join-Path $Path "_framework"
    if (!(Test-Path $WorkingDir)) { Throw "Wrong path $Path. current location must be wwwroot folder of published application." }

    # Get All Items
    $AllItems = Get-ChildItem $WorkingDir -Recurse
    $DLLs = $AllItems | Where-Object { $_.Name -like '*.dll*' }
    $BINs = $AllItems | Where-Object { $_.Name -like '*.bin*' }

    # End script if no .dll are found
    if ($DLLs) { 

        # Delete all current .bin files
        if ($BINs) {
            Remove-item $BINs.FullName -Force
        }
    
        # Change .dll to .bin on files and config
        $DLLs | Rename-item -NewName { $_.Name -replace ".dll\b",".bin" }
        ((Get-Content "$WorkingDir\blazor.boot.json" -Raw) -replace '.dll"','.bin"') | Set-Content "$WorkingDir\blazor.boot.json"
    
        # Delete Compressed Blazor files
        if (Test-Path "$WorkingDir\blazor.boot.json.gz") {
            Remove-Item "$WorkingDir\blazor.boot.json.gz"
        }
        if (Test-Path "$WorkingDir\blazor.boot.json.br") {
            Remove-Item "$WorkingDir\blazor.boot.json.br"
        }
    
        # Do the same for ServiceWorker, if it exists
        $ServiceWorker = Get-Item "$Path\service-worker-assets.js" -ErrorAction SilentlyContinue
        if ($ServiceWorker) {
            ((Get-Content $ServiceWorker.FullName -Raw) -replace '.dll"','.bin"') | Set-Content $ServiceWorker.FullName
            Remove-Item ($ServiceWorker.FullName + ".gz")
            Remove-Item ($ServiceWorker.FullName + ".br")
        }
    }
    else {
        Write-Host "There are no .dll Files to rename to .bin" 
    }
}

Basically you need to navigate to the wwwroot folder of your published application and run the function there. e.g:

PS D:\inetpub\wwwroot\<appname>\wwwroot> Hide-BlazorDLL

Solution for me was to delete the obj and the bin folder in both the client and the server project folder

We have experienced this issue using Cloudflare auto minify feature. That feature removes any comments from html, js and other files - which some of the blazor .js files seems to contain.

This means that the hash of the file contents no longer matches the hash found in blazor.boot.json -> an integrity issue will be thrown and stop the app from loading.

Disabling the auto minify feature fixed the issue.

This error for some reason kept happening for me when I tested my application in an anonymous browser window (Google Chrome).

Try using a normal browser window if you're getting integrity errors.

Also, if you're using Cloudflare CDN don't forget to "Purge Everything" in the cache.