Visual Studio Reporting Duplicate Schema Item in AppSettingsSchema

Area with issue?

JSON Schema

✔️ Expected Behavior

No reported schema errors

❌ Actual Behavior

Today (September 8th), Visual Studio 2026 started reporting issues on all my appsettings.json files. The message in the error window (under the Messages tab) is:

There are problems with this document's schema impacting one or more items in the document. Please report this issue to schema owner.

checking the Output --> JSON window, I get this message per file:

There are problems with this document's schema impacting one or more items in the document. Please report this issue to schema owner.

    Items must be unique
    at (line 1094, column 9) in document C:\Product\Solution_Folder\Project_Folder\obj\Debug\net10.0\appsettingsschema.json
    at schema text "CredentialSource"

Opening the file I do see CredentialSource listed twice on Line 1094:

I did try closing VS completely, deleting the bin and obj folders (for every project in the solution), re-open, clean solution, but it immediately grabs the AppSettingsSchema.json file and reports the same error.

JSON, YAML, or TOML file that does not work.

No response

IDE or code editor.

Visual Studio

Are you making a PR for this?

No, someone else must create the PR.

Start by locating the source for the generated obj/Debug/net10.0/appsettingsschema.json and inspect the duplicate CredentialSource entries around line 1094. Reproduce the schema validation error in Visual Studio against an appsettings.json file; done when the generated schema contains one unique CredentialSource and the error no longer appears.