This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(25.6, 82%, 12%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EDD%3C/text%3E%3C/svg%3E)
I'm experiencing what appears to be a false positive warning in my Azure Function App regarding the worker runtime configuration.
The warning states:
"We've noticed that your function app is configured with the FUNCTIONS_WORKER_RUNTIME setting as "dotnet-isolated", but expected value for the deployed application payload is "CSharp". This is an unoptimized state which limits performance and may impact application reliability..."
However, our application is explicitly designed and configured to use the isolated worker model with .NET 8.0. Here are the relevant configuration details:
- <TargetFramework>net8.0</TargetFramework>
- <AzureFunctionsVersion>v4</AzureFunctionsVersion>
- <OutputType>Exe</OutputType>
- We reference Microsoft.Azure.Functions.Worker and Microsoft.Azure.Functions.Worker.Sdk packages
This warning appears to be a false positive in the detection logic, possibly related to our use of .NET 8.0 with the isolated worker model. The warning mentions it will be raised to an Error level in a future update, which would cause significant issues for our application as changing to "dotnet" runtime would break our isolated worker functionality.
Has anyone else encountered this issue with .NET 8.0 isolated function apps? Is this a known issue with the detection logic? Any workarounds or should I just ignore the warning?
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(265.6, 22%, 35%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ESE%3C/text%3E%3C/svg%3E)
Hi Daniil Demidov,
Just checking in to see if the below answer provided by Daniel Bates helped.
if you have any further query do let us know.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(41.6, 13%, 14%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EPK%3C/text%3E%3C/svg%3E)
Daniil Demidov, This error occurs when a function app has a FUNCTIONS_WORKER_RUNTIME setting specifying dotnet-isolated as language stack, but a payload for dotnet is deployed to it. Validate your function code and project structure, make sure it supports dotnet-isolated. Refer MSDOC.
Daniil Demidov, Just checking in to see if the above provided information helped. If you have any further queries, do let us know.
Daniil Demidov, We still have not heard back from you. Could you please let us know if the provided information helped? Additionally, if you have any further questions, please let us know.
@Pravallika Kothaveeranna Gari It did not help.
Daniil Demidov, Let's continue the discussion in Private Messages.
Here is the reference link on How to access & Data Privacy policy of private messages in Microsoft QnA.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(134.4, 33%, 23%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3ES7%3C/text%3E%3C/svg%3E)
We're experiencing the same issue. To isolated it's not the code we have, I created an brand new project using the .NET 8 isolated with the default "SayHello" template generated by Visual Studio 2022. Then, I deployed the exact same code to two environments:
Both of the deployments used these environment settings:
FUNCTIONS_WORKER_RUNTIME = dotnet-isolated
FUNCTIONS_EXTENSION_VERSION = ~4
WEBSITE_USE_PLACEHOLDER_DOTNETISOLATED = 1
Surprisingly, the brand new Function App does not show the warning, while the existing upgraded Function App still does. I also tested switching between 32-bit and 64-bit, and toggling WEBSITE_RUN_FROM_PACKAGE (1 and 0), but none of those made a difference. I read somewhere saying metadata is an issue, so I logged on to Kudu of the existing Function App and tried to delete any old files, re-deployed and restarted, unfortunately it didn't help.
Has anyone else observed this behavior or found a solution? Any insights would be appreciated! Thanks!
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(12.8, 19%, 11%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EDB%3C/text%3E%3C/svg%3E)
Microsoft has already declared the .NET apps with the in-process model (FUNCTIONS_WORKER_RUNTIME = dotnet) deprecated and will end support November 2026. We're actually told that everyone needs to switch to the isolated worker model (FUNCTIONS_WORKER_RUNTIME = dotnet-isolated)