how to fix this error when i do npm start it say "cannot find module

[kylinekyline]

hello friends i am try run my project with nodejs and reactjs
i install all dependancy with npm install but when i do npm start it show error
Error: Cannot find module 'dotenv'

but i already put it in package.json and i do install many time

what is the problem pls help i am confuse

[kleinborre]

I think the issue is that dotenv is listed under devDependencies, and when you run npm install --production, it skips those packages. Try just running npm install dotenv to add it directly. Also, it's a good idea to check if the package is actually in your node_modules folder when errors like this come up.

[fahaddev19]

If you're getting the error "Error: Cannot find module 'dotenv'" even after running npm install, it's likely because the dotenv package was either not properly installed or installed in the wrong folder. First, make sure you are in the correct directory — if your project has separate folders for the frontend (React) and backend (Node.js), this error usually comes from the backend side, so switch to your backend folder using cd backend (or the correct path). Then, run npm install dotenv to install the package manually. After that, check that you're using dotenv correctly by adding require('dotenv').config(); at the very top of your main server file, such as index.js or server.js. If the issue still doesn't go away, try deleting the node_modules folder and package-lock.json file using rm -rf node_modules package-lock.json, then run npm install again to reinstall all dependencies. Finally, run your app using npm start. This should resolve the error and load environment variables properly