Template creation throws an exception: `dotnet new android`, `dotnet new maui-blazor`

[matouskozak]

Product

dotnet CLI (dotnet new)

Describe The Bug

When using the latest .NET SDK and MAUI workload, we encountered an exception when creating an android sample template app.

Error: Failed to load template from D:\a\1\s\performance\CorrelationStaging\payload\dotnet\template-packs\microsoft.maui.templates.net11.11.0.0-preview.1.26160.5.nupkg(/content/templates/maui-blazor-solution/.template.config/template.json).
2026-03-19T00:07:38.5985217Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO] Details: System.ArgumentException: An item with the same key has already been added. Key: empty (Parameter 'key')
2026-03-19T00:07:38.5995938Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Collections.ThrowHelper.ThrowDuplicateKey[TKey](TKey key)
2026-03-19T00:07:38.5996835Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Collections.Generic.OrderedDictionary`2.TryInsert(Int32 index, TKey key, TValue value, InsertionBehavior behavior, Int32& keyIndex)
2026-03-19T00:07:38.6012459Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Collections.Generic.OrderedDictionary`2.Add(TKey key, TValue value)
2026-03-19T00:07:38.6013157Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Text.Json.Nodes.JsonObject.InitializeDictionary()
2026-03-19T00:07:38.6021050Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Text.Json.Nodes.JsonObject.get_Count()
2026-03-19T00:07:38.6021765Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
2026-03-19T00:07:38.6030264Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
2026-03-19T00:07:38.6031717Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at Microsoft.TemplateEngine.Orchestrator.RunnableProjects.ConfigModel.TemplateConfigModel..ctor(JsonObject source, ILogger logger, String baselineName)
2026-03-19T00:07:38.6032759Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at Microsoft.TemplateEngine.Orchestrator.RunnableProjects.DirectoryBasedTemplate..ctor(IEngineEnvironmentSettings settings, IGenerator generator, IFile templateFile, String baselineName)
2026-03-19T00:07:38.6033692Z [2026/03/19 00:07:38][INFO]   [2026/03/19 00:07:38][INFO]    at Microsoft.TemplateEngine.Orchestrator.RunnableProjects.RunnableProjectGenerator.GetTemplatesFromMountPointInternalAsync(IMountPoint source, CancellationToken cancellationToken)

Build: https://dev.azure.com/dnceng/internal/_build/results?buildId=2930171&view=logs&j=5a4a2c52-3fd8-5d7a-009a-f42c0ca84580&t=fc484750-7d5f-5d47-8c70-e5b4516a9cf3

To Reproduce

Steps:

1. Install the latest .NET SDK and MAUI workload
2. dotnet new android --output app --name NetAndroidDefault

dotnet Info

output

.NET SDK: Version: 11.0.100-preview.3.26168.106 Commit: 803eb28628 Workload version: 11.0.100-manifests.76d4304b MSBuild version: 18.6.0-preview-26168-106+803eb2862 2026-03-19T00:07:37.8244127Z [2026/03/19 00:07:37][INFO] Runtime Environment: OS Name: Windows OS Version: 10.0.20348 OS Platform: Windows RID: win-x64 Base Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk\11.0.100-preview.3.26168.106\ 2026-03-19T00:07:37.8341847Z [2026/03/19 00:07:37][INFO] .NET workloads installed: [maui] Installation Source: SDK 11.0.100-preview.3 Manifest Version: 11.0.0-preview.1.26160.5/11.0.100-preview.3 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100-preview.3\microsoft.net.sdk.maui\11.0.0-preview.1.26160.5\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9292138Z [2026/03/19 00:07:37][INFO] [maui-windows] Installation Source: VS 17.14.37012.4 Manifest Version: 11.0.0-preview.1.26160.5/11.0.100-preview.3 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100-preview.3\microsoft.net.sdk.maui\11.0.0-preview.1.26160.5\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9343635Z [2026/03/19 00:07:37][INFO] [maccatalyst] Installation Source: VS 17.14.37012.4 Manifest Version: 26.2.11548-net11-p3/11.0.100-preview.3 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100-preview.3\microsoft.net.sdk.maccatalyst\26.2.11548-net11-p3\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9346417Z [2026/03/19 00:07:37][INFO] [ios] Installation Source: VS 17.14.37012.4 Manifest Version: 26.2.11548-net11-p3/11.0.100-preview.3 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100-preview.3\microsoft.net.sdk.ios\26.2.11548-net11-p3\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9349061Z [2026/03/19 00:07:37][INFO] [android] Installation Source: VS 17.14.37012.4 Manifest Version: 36.1.99-ci.main.217/11.0.100-preview.3 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100-preview.3\microsoft.net.sdk.android\36.1.99-ci.main.217\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9352057Z [2026/03/19 00:07:37][INFO] [wasm-tools] Installation Source: VS 17.14.37012.4 Manifest Version: 11.0.100-preview.3.26168.106/11.0.100 Manifest Path: D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk-manifests\11.0.100\microsoft.net.workload.mono.toolchain.current\11.0.100-preview.3.26168.106\WorkloadManifest.json Install Type: FileBased 2026-03-19T00:07:37.9355113Z [2026/03/19 00:07:37][INFO] Configured to use loose manifests when installing new manifests. 2026-03-19T00:07:37.9355967Z [2026/03/19 00:07:37][INFO] Host: Version: 11.0.0-preview.3.26168.106 Architecture: x64 Commit: 803eb28628 2026-03-19T00:07:37.9358105Z [2026/03/19 00:07:37][INFO] .NET SDKs installed: 11.0.100-preview.3.26168.106 [D:\a\1\s\performance\CorrelationStaging\payload\dotnet\sdk] 2026-03-19T00:07:37.9359517Z [2026/03/19 00:07:37][INFO] .NET runtimes installed: Microsoft.AspNetCore.App 11.0.0-preview.3.26168.106 [D:\a\1\s\performance\CorrelationStaging\payload\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 11.0.0-preview.3.26168.106 [D:\a\1\s\performance\CorrelationStaging\payload\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 11.0.0-preview.3.26168.106 [D:\a\1\s\performance\CorrelationStaging\payload\dotnet\shared\Microsoft.WindowsDesktop.App]

Visual Studio Version

No response

Additional context

No response

[matouskozak]

In the same run, we're seeing another error possibly related to this:

dotnet new maui-blazor --output app --force --name MauiBlazorAndroidDefault
No templates or subcommands found matching: 'maui-blazor'