"Property Not Allowed" in angular.json error in Visual Studio CODE for Angular CLI version 9.1.1

The schema is case sensitive. If you wish to fix:

Goto: ./node_modules/@angular/cli/lib/config/schema.json

At around line 27 you should find:

 "projects": {
      "type": "object",
      "patternProperties": {
        "^(?:@[a-z0-9-~][a-z0-9-._~]*\/)?[a-z0-9-~][a-z0-9-._~]*$": {
          "$ref": "#/definitions/project"
        }
      },

Change the regex pattern to allow Uppercase project names:

"^(?:@[a-zA-Z0-9-~][a-zA-Z0-9-._~]*\/)?[a-zA-Z0-9-~][a-zA-Z0-9-._~]*$"

The error was gone when change project name and all other occurrences for it in "angular.json" to lowercase letters. no need to create another project or any other stuff.

The packages installed for Angular 10 project have a change in project name structure.

The file named "schema.json" which come along the packages installed by Angular has a property name "projects" which has the schema structure defined for the project name.

It looks like this:

"projects": {
  "type": "object",
  "patternProperties": {
      "^(?:@[a-z0-9-~][a-z0-9-._~]*\/)?[a-z0-9-~][a-z0-9-._~]*$": {
      "$ref": "#/definitions/project"
    }
  }

It is configured for lower case project names. You simply have to change the regex so that your uppercase project names can be considered.

Change the code as below:

"projects": {
  "type": "object",
  "patternProperties": {
    "^(?:@[a-zA-Z0-9-~][a-zA-Z0-9-._~]*\/)?[a-zA-Z0-9-~][a-zA-Z0-9-._~]*$": {
      "$ref": "#/definitions/project"
    }
  }

The schema.json is located at below path:

./node_modules/@angular/cli/lib/config/schema.json

After the change in schema.json file, restart your Visual Code Editor.

It is working fine on stackblitz, sometimes VS code behaves strangely. Try closing VS code and opening again, that helps most of the times in these cases

working example https://stackblitz.com/edit/angular-dhtbbh

There are 2 solutions which works for me 100% to overcome from the problem of "Property not allowed" in angular.json file.

1. Use the command in VS code cmd Ctrl+C choose option Y or

2. Restart the VS code after editing in angular.json file Hope it will helpful.

Change the project name in all the .json files

The error is resolved by creating another project but this time using the project name in lowercase letters.