1- press ctrl + shift + p in windows or linux or command + shift + p in mac

2- type TSLint: Manage workspace library execution

3- choose Always enable workspace library execution

or you can save workspace file => Save workspace as

Press Ctrl+Shift+P to open command pallete.

In the input that pops up at the top of the VS Code, write

TSLint: Manage workspace library execution

From the menu that replaces the input, pick

Enable Workspace Library Execution

You should go to Command Palette in VScode to search for TSLint: Manage workspace library execution. And enable workspace library execution

Like @Tuấn Nguyễn described, you need to:

1. Go to Command Palette by pressing Ctrl + Shift + P,

2. In the input that pops up at the top of the VS Code, start typing

   TSLint: Manage workspace library execution"
   

   and hit Enter key.

3. From the menu that replaces the input, pick enable workspace library execution and again press Enter key.

1. install globally typescript
2. a;Try to configure your IDE
3. execute: npm i typescript -g

I fixed the issue in this easy way:

File -> Save Workspace As...

by saving the workspace, vscode detect some libraries and work better in files

Jump to the error. Hover over the lightbulb and you will see the option. Click it and you must be getting the prompt to allow it.

This is how I fixed it myself recently

https://github.com/microsoft/vscode-eslint Here is a link with a more detailed guide. Multiple steps on how to do it (including the other answers here)

This probably is a security thing from VScode to prevent bad things from happening in your code

Answering QUESTION 2: yes you should uninstall TSLint and migrate to ESLint since TSLint has been deprecated from Microsoft. This link might help you.

Although the answer given by @Tuấn Nguyễn works yet it is not advisable to do so.

As per MS docs https://marketplace.visualstudio.com/items?itemName=ms-vscode.vscode-typescript-tslint-plugin, this answer will replace the global TS lint configuration defined with the local one, which one can manipulate easily and its not recommended due to security reasons as well.

Screenshot:

Recommended Approach:

As per MS Docs, https://code.visualstudio.com/api/advanced-topics/tslint-eslint-migration, updated recently (12/11/2020), you should migrate from TSLint to ESLint.

This might be the reason that everyone is looking for the fix, as needful things were done by MS recently. :)

Steps:

1. npm install --save-dev eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin (Install ESlint and TSLint)
2. npx tslint-to-eslint-config (This will install utility tool and make configuration easier. Post install a new .eslintrc.js will be created. There will be changes to .vscode/settings.json as well.)
3. Disable/Uninstall TS lint from your VS Code.
4. You can then, place a script in your package.json file as - "lint": "eslint -c .eslintrc.js --ext .ts <mySrcFolder>". (This will tell ESLint to look for TSLint)

But, you should probably look once, over steps in link more vividly, in order to follow steps correctly and accordingly.

Go to Command Palette by pressing Ctrl + Shift + P,

In the input that pops up at the top of the VS Code, start typing

TSLint: Manage workspace library execution" and hit Enter.

From the menu that replaces the input, pick enable workspace library execution, and again hit Enter.