Azure
Logic Apps Designer does not start
Severity
P1 - Critical (Blocking production)
Describe the Bug with repro steps
I just prepared a Logic App Developer environment for one of our customers for demo purposes. I created a new Logic App Workspace and a Workflow. When I try to open the designer I get the error-log you will find below. I tried it on two brand new machines. X64 and ARM64. I just installed Visual Studio Code and the Logic Apps Standard Extension. On both machines/Architectures I get the same result:
Please see the error-logs below: C:\Dev\LogicApps\Demo> C:\Users\sebas.azurelogicapps\dependencies\FuncCoreTools\func host start --port 8000 --verbose FUNCTIONS_INPROC_NET8_ENABLED app setting enabled in local.settings.json Selected inproc8 host. Starting child process for inproc8 model host. C:\Users\sebas.azurelogicapps\dependencies\FuncCoreTools\in-proc8\func.exe present Started child process with ID: 4436 %%%%%% %%%%%% @ %%%%%% @ @@ %%%%%% @@ @@@ %%%%%%%%%%% @@@ @@ %%%%%%%%%% @@ @@ %%%% @@ @@ %%% @@ @@ %% @@ %% % Azure Functions Core Tools Core Tools Version: 4.1.0+9a53409b640bbb39ef49467f000f46c5d81d4bbf (64-bit) Function Runtime Version: 4.40.100.25262 [2025-08-06T17:42:58.124Z] Csproj not found in C:\Dev\LogicApps\Demo directory tree. Skipping user secrets file configuration. [2025-08-06T17:42:58.319Z] Building host: version spec: , startup suppressed: 'False', configuration suppressed: 'False', startup operation id: 'd781ce65-8627-4026-9dbb-e0ca0ef9dcbb' [2025-08-06T17:42:58.323Z] Reading host configuration file 'C:\Dev\LogicApps\Demo\host.json' [2025-08-06T17:42:58.324Z] Host configuration file read: [2025-08-06T17:42:58.332Z] { [2025-08-06T17:42:58.333Z] "version": "2.0", [2025-08-06T17:42:58.334Z] "logging": { [2025-08-06T17:42:58.334Z] "applicationInsights": { [2025-08-06T17:42:58.335Z] "samplingSettings": { [2025-08-06T17:42:58.335Z] "isEnabled": true, [2025-08-06T17:42:58.337Z] "excludedTypes": "Request" [2025-08-06T17:42:58.337Z] } [2025-08-06T17:42:58.338Z] } [2025-08-06T17:42:58.338Z] }, [2025-08-06T17:42:58.338Z] "extensionBundle": { [2025-08-06T17:42:58.338Z] "id": "Microsoft.Azure.Functions.ExtensionBundle.Workflows", [2025-08-06T17:42:58.339Z] "version": "[1., 2.0.0)" [2025-08-06T17:42:58.339Z] } [2025-08-06T17:42:58.339Z] } [2025-08-06T17:42:58.368Z] Found multi-language runtime environment. Starting WorkerConfig for language: java [2025-08-06T17:42:58.370Z] Found multi-language runtime environment. Starting WorkerConfig for language: node [2025-08-06T17:42:58.377Z] Found multi-language runtime environment. Starting WorkerConfig for language: powershell [2025-08-06T17:42:58.379Z] Looking for extension bundle Microsoft.Azure.Functions.ExtensionBundle.Workflows at C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows [2025-08-06T17:42:58.379Z] Applying platform release channel configuration LATEST. Bundle version 1.131.9 will be used [2025-08-06T17:42:58.380Z] Found a matching extension bundle at C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows\1.131.9 [2025-08-06T17:42:58.387Z] Loading functions metadata [2025-08-06T17:42:58.389Z] Reading functions metadata (Host) [2025-08-06T17:42:58.392Z] 0 functions found (Host) [2025-08-06T17:42:58.396Z] 0 functions loaded [2025-08-06T17:42:58.397Z] Looking for extension bundle Microsoft.Azure.Functions.ExtensionBundle.Workflows at C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows [2025-08-06T17:42:58.398Z] Applying platform release channel configuration LATEST. Bundle version 1.131.9 will be used [2025-08-06T17:42:58.399Z] Found a matching extension bundle at C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows\1.131.9 [2025-08-06T17:42:58.399Z] Fetching information on versions of extension bundle Microsoft.Azure.Functions.ExtensionBundle.Workflows available on https://cdn.functions.azure.com/public/ExtensionBundles/Microsoft.Azure.Functions.ExtensionBundle.Workflows/index.json [2025-08-06T17:42:58.566Z] Applying platform release channel configuration LATEST. Bundle version 1.131.9 will be used [2025-08-06T17:42:58.569Z] Skipping bundle download since it already exists at path C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows\1.131.9 [2025-08-06T17:42:58.597Z] Loading extension bundle from C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows\1.131.9\bin [2025-08-06T17:42:58.598Z] Script Startup resetting load context with base path: 'C:\Users\sebas.azure-functions-core-tools\Functions\ExtensionBundles\Microsoft.Azure.Functions.ExtensionBundle.Workflows\1.131.9\bin'. [2025-08-06T17:42:58.603Z] Loading startup extension 'CosmosDB' [2025-08-06T17:42:58.652Z] Loaded extension 'CosmosDB' (4.6.1.0) [2025-08-06T17:42:58.660Z] Loading startup extension 'EventGrid' [2025-08-06T17:42:58.661Z] Loaded extension 'EventGrid' (3.2.0.0) [2025-08-06T17:42:58.662Z] Loading startup extension 'EventHubs' [2025-08-06T17:42:58.663Z] Loaded extension 'EventHubs' (6.3.5.0) [2025-08-06T17:42:58.664Z] Loading startup extension 'Kafka' [2025-08-06T17:42:58.665Z] Loaded extension 'Kafka' (4.0.0.0) [2025-08-06T17:42:58.666Z] Loading startup extension 'RabbitMQ' [2025-08-06T17:42:58.666Z] Loaded extension 'RabbitMQ' (2.0.3.0) [2025-08-06T17:42:58.667Z] Loading startup extension 'ServiceBus' [2025-08-06T17:42:58.668Z] Loaded extension 'ServiceBus' (5.14.0.0) [2025-08-06T17:42:58.668Z] Loading startup extension 'SqlBinding' [2025-08-06T17:42:58.669Z] Loaded extension 'SqlBinding' (3.1.284.0) [2025-08-06T17:42:58.669Z] Loading startup extension 'AzureStorageBlobs' [2025-08-06T17:42:58.670Z] Loaded extension 'AzureStorageBlobs' (5.2.1.0) [2025-08-06T17:42:58.670Z] Loading startup extension 'AzureStorageQueues' [2025-08-06T17:42:58.671Z] Loaded extension 'AzureStorageQueues' (5.1.3.0) [2025-08-06T17:42:58.671Z] Loading startup extension 'ScriptingExtension' [2025-08-06T17:42:58.672Z] Loaded extension 'ScriptingExtension' (1.131.9.0) [2025-08-06T17:42:58.672Z] Loading startup extension 'ACASessionServiceProvider' [2025-08-06T17:42:58.673Z] Loaded extension 'ACASessionServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.673Z] Loading startup extension 'AutomationServiceProvider' [2025-08-06T17:42:58.674Z] Loaded extension 'AutomationServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.674Z] Loading startup extension 'AzureAISearchProvider' [2025-08-06T17:42:58.674Z] Loaded extension 'AzureAISearchProvider' (1.131.9.0) [2025-08-06T17:42:58.675Z] Loading startup extension 'AzureBlobServiceProvider' [2025-08-06T17:42:58.676Z] Loaded extension 'AzureBlobServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.676Z] Loading startup extension 'AzureFileServiceProvider' [2025-08-06T17:42:58.677Z] Loaded extension 'AzureFileServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.677Z] Loading startup extension 'QueueServiceProvider' [2025-08-06T17:42:58.678Z] Loaded extension 'QueueServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.678Z] Loading startup extension 'AzureTablesServiceProvider' [2025-08-06T17:42:58.678Z] Loaded extension 'AzureTablesServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.679Z] Loading startup extension 'CicsProgramCallServiceProvider' [2025-08-06T17:42:58.679Z] Loaded extension 'CicsProgramCallServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.679Z] Loading startup extension 'ConfluentKafkaServiceProvider' [2025-08-06T17:42:58.680Z] Loaded extension 'ConfluentKafkaServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.680Z] Loading startup extension 'CosmosDBServiceProvider' [2025-08-06T17:42:58.681Z] Loaded extension 'CosmosDBServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.681Z] Loading startup extension 'DB2ServiceProvider' [2025-08-06T17:42:58.682Z] Loaded extension 'DB2ServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.682Z] Loading startup extension 'DocumentIntelligenceServiceProvider' [2025-08-06T17:42:58.683Z] Loaded extension 'DocumentIntelligenceServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.683Z] Loading startup extension 'EventGridPublisherServiceProvider' [2025-08-06T17:42:58.684Z] Loaded extension 'EventGridPublisherServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.684Z] Loading startup extension 'EventHubsServiceProvider' [2025-08-06T17:42:58.685Z] Loaded extension 'EventHubsServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.685Z] Loading startup extension 'FileSystemServiceProvider' [2025-08-06T17:42:58.686Z] Loaded extension 'FileSystemServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.686Z] Loading startup extension 'FtpServiceProvider' [2025-08-06T17:42:58.687Z] Loaded extension 'FtpServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.687Z] Loading startup extension 'HostFileServiceProvider' [2025-08-06T17:42:58.688Z] Loaded extension 'HostFileServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.688Z] Loading startup extension 'IbmIProgramCallServiceProvider' [2025-08-06T17:42:58.689Z] Loaded extension 'IbmIProgramCallServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.689Z] Loading startup extension 'ImsProgramCallServiceProvider' [2025-08-06T17:42:58.690Z] Loaded extension 'ImsProgramCallServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.691Z] Loading startup extension 'JdbcServiceProvider' [2025-08-06T17:42:58.691Z] Loaded extension 'JdbcServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.692Z] Loading startup extension 'KeyVaultServiceProvider' [2025-08-06T17:42:58.692Z] Loaded extension 'KeyVaultServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.693Z] Loading startup extension 'MqServiceProvider' [2025-08-06T17:42:58.694Z] Loaded extension 'MqServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.694Z] Loading startup extension 'OpenAiServiceProvider' [2025-08-06T17:42:58.695Z] Loaded extension 'OpenAiServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.695Z] Loading startup extension 'RabbitMQServiceProvider' [2025-08-06T17:42:58.696Z] Loaded extension 'RabbitMQServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.696Z] Loading startup extension 'SapServiceProvider' [2025-08-06T17:42:58.697Z] Loaded extension 'SapServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.697Z] Loading startup extension 'ServiceBusServiceProvider' [2025-08-06T17:42:58.698Z] Loaded extension 'ServiceBusServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.699Z] Loading startup extension 'SftpServiceProvider' [2025-08-06T17:42:58.699Z] Loaded extension 'SftpServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.700Z] Loading startup extension 'Si3270ServiceProvider' [2025-08-06T17:42:58.700Z] Loaded extension 'Si3270ServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.701Z] Loading startup extension 'SmtpServiceProvider' [2025-08-06T17:42:58.701Z] Loaded extension 'SmtpServiceProvider' (0.0.0.0) [2025-08-06T17:42:58.702Z] Loading startup extension 'SqlServiceProvider' [2025-08-06T17:42:58.702Z] Loaded extension 'SqlServiceProvider' (1.131.9.0) [2025-08-06T17:42:58.703Z] Loading startup extension 'WorkflowExtension' [2025-08-06T17:42:58.703Z] Loaded extension 'WorkflowExtension' (1.131.9.0) [2025-08-06T17:42:58.713Z] Reading host configuration file 'C:\Dev\LogicApps\Demo\host.json' [2025-08-06T17:42:58.714Z] Host configuration file read: [2025-08-06T17:42:58.714Z] { [2025-08-06T17:42:58.714Z] "version": "2.0", [2025-08-06T17:42:58.715Z] "logging": { [2025-08-06T17:42:58.715Z] "applicationInsights": { [2025-08-06T17:42:58.715Z] "samplingSettings": { [2025-08-06T17:42:58.716Z] "isEnabled": true, [2025-08-06T17:42:58.716Z] "excludedTypes": "Request" [2025-08-06T17:42:58.716Z] } [2025-08-06T17:42:58.717Z] } [2025-08-06T17:42:58.717Z] }, [2025-08-06T17:42:58.717Z] "extensionBundle": { [2025-08-06T17:42:58.718Z] "id": "Microsoft.Azure.Functions.ExtensionBundle.Workflows", [2025-08-06T17:42:58.718Z] "version": "[1., 2.0.0)" [2025-08-06T17:42:58.718Z] } [2025-08-06T17:42:58.719Z] } [2025-08-06T17:42:58.762Z] Error configuring services in an external startup class. [2025-08-06T17:42:58.763Z] Error configuring services in an external startup class. System.Private.CoreLib: An attempt was made to load a program with an incorrect format. (0x8007000B). [2025-08-06T17:42:58.848Z] A host error has occurred during startup operation 'd781ce65-8627-4026-9dbb-e0ca0ef9dcbb'. [2025-08-06T17:42:58.849Z] Microsoft.Azure.WebJobs.Script: Error configuring services in an external startup class. System.Private.CoreLib: An attempt was made to load a program with an incorrect format. (0x8007000B). Value cannot be null. (Parameter 'provider') [2025-08-06T17:42:58.856Z] Host startup operation has been canceled [2025-08-06T17:42:58.857Z] Initialization cancellation requested by runtime. [2025-08-06T17:42:58.859Z] Stopping host... [2025-08-06T17:42:58.860Z] Host shutdown completed.
What type of Logic App Is this happening in?
Standard (VSCode)
Are you experiencing a regression?
No response
Which operating system are you using?
Windows
Did you refer to the TSG before filing this issue? https://aka.ms/lauxtsg
Yes
Workflow JSON
Screenshots or Videos
No response
Environment
- LA Extension: 5.30.9
- Extension Bundle: 1.131.9
Additional context
No response
@sebastianmeyer-1 can you also share with us your workflow-designtime/local.settings.json and the local.setting.json from the main Logic Apps folder?
@wsilveiranz workflow-designtime/local.settings.json: { "IsEncrypted": false, "Values": { "APP_KIND": "workflowapp", "ProjectDirectoryPath": "c:\dev\logicapps\demos", "FUNCTIONS_WORKER_RUNTIME": "node", "AzureWebJobsSecretStorageType": "Files" } }
local.settings.json from the main Logic Apps folder: { "IsEncrypted": false, "Values": { "AzureWebJobsStorage": "UseDevelopmentStorage=true", "FUNCTIONS_INPROC_NET8_ENABLED": "1", "FUNCTIONS_WORKER_RUNTIME": "dotnet", "APP_KIND": "workflowapp", "ProjectDirectoryPath": "c:\dev\logicapps\demos", "WORKFLOWS_SUBSCRIPTION_ID": "" } }
@wsilveiranz I re-installed the extension on the x64 Machine and it is working now. On ARM64 it is not working!
Hi @sebastianmeyer-1 thanks for letting us know about this. This error is popping up from backend. @AbodeSaafan Do you know if there is a different extension budle for ARM64 and x64?
@sebastianmeyer-1 Checking with team and will get back to you on here (will close https://github.com/Azure/logicapps/issues/1409#issuecomment-3161075337 for now since it seems like a repeat?)
Following up here because I not only have a workaround, but I know why this issue is happening and have a suggested solution.
TL;DR;
Cause: There is no Azure Functions Python Worker for Windows ARM64 but the Visual Studio Code Logic Apps (Standard) Extension downloads the Azure Functions Core Tools Windows ARM64 package.
Workaround:
- Download the Azure Functions Core Tools Windows X64 package latest here and copy the contents over the
%USERPROFILE%\.azurelogicapps\dependencies\FuncCoreToolsfolder - Update the
worker.config.jsonfile in%USERPROFILE%\.azurelogicapps\dependencies\FuncCoreTools\workers\pythonto changedefaultWorkerPathto%FUNCTIONS_WORKER_RUNTIME_VERSION%/{os}/X64/worker.py(note the hard-codedX64)
Preface
I run Windows on ARM on an M1 MacBook Pro and I only work with Standard Logic Apps without any C# (or otherwise) code behind. So, YMMV.
Here Be Dragons
Now, into how this convoluted web of dependencies has caused this issue:
Azure Logic Apps (Standard)
The Azure Logic Apps (Standard) Extension is configured by default to use its own dependencies for Azurite, the .NET SDK, and Azure Functions Core Tools. The Extension is platform- and architecture-aware, so it downloads the packages for your specific OS and processor combination (e.g., win_ARM64). This ensures the dependencies are there and in the correct versions.
Downloading its own dependencies means any version(s) you install manually (i.e., through winget, Chocolatey, etc.) will have no effect on the version the Extension uses. You can override where the Extension finds its dependencies, but I suspect most people don't.
Because the Extension gives you the Windows ARM64 versions of Azurite, the .NET SDK, and Azure Functions Core Tools, you run headlong into the fact there is no Azure Functions Python Worker for Windows ARM64. This results in the error messages people are seeing with Error configuring services in an external startup class. System.Private.CoreLib: An attempt was made to load a program with an incorrect format. (0x8007000B), because the Windows ARM64-version of the Azure Functions Python Worker isn't there when the Functions Runtime expects it to be.
This is why the workaround is downloading the Windows X64 version of the Azure Functions Core Tools over the Extension's ARM64 version and then updating where the Functions Runtime finds its Python Worker from defaultWorkerPath in worker.config.json. If you don't update worker.config.json, you'll run into a different error relating to not being able to find the file .../WINDOWS/ARM64/worker.py.
Azure Functions Core Tools
That leads us to the question of "Why isn't there a Windows ARM64 Python Worker in Azure Functions Core Tools?"
The answer is because there's no Windows ARM64 version of the underlying Azure Functions Python Worker (see Azure/azure-functions-core-tools/issues/4262).
Azure Functions Python Worker
Moving on to the Azure Functions Python Worker, there is Azure/azure-functions-python-worker/issues/1714 which mentions there's a dependency on grpcio that team is waiting on until they can support Windows ARM64.
grpcio
We finally get to grpcio, which has grpc/grpc/issues/39362 requesting the team create a Windows ARM64 version. Unfortunately, limitations within Google's CI system (Kokoro) prevent them from supporting Windows ARM64 anytime soon. They cannot get a supported Windows on ARM VM (no public Windows Server on ARM build and no Google-built GCP images for Windows Client on ARM).
Thus, there will not by any Windows ARM64 support for Logic Apps for the foreseeable future and the only workaround is to use the Windows X64 version of the Azure Functions Core Tools.
Other people are already attempting to help the grpcio team resolve their Windows ARM64 issues but the team does not appear to be prioritizing it.
Suggested Solution
The solution I propose is for the Azure Logic Apps (Standard) Extension to install the Windows X64 version of its dependencies, which all work on Windows on ARM, when it detects Windows ARM64 until such time that the Azure Functions Python Worker supports Windows ARM64.
The reason I suggest this solution is because there aren't really any alternatives (i.e., dependent libraries have open Issues punting to a lower dependency) and the workaround breaks every time the Extension updates its dependencies.
@lambrianmsft I think you were looking into the missing python worker before? Do we have a solution for this for ARM64/can we apply the above solution?
