invalid library

hi,

i am a new arduino developer and upon loading the arduino ide, there is a warning message.
in fact i have installed this library and the boards as well.

i also noticed that there is a duplicate in the board list.

\Invalid library found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0: no headers files (.h) found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0
Invalid library found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0: no headers files (.h) found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0

Wow, it looks like you've been very busy installing the ESP8266 core for Arduino all over the place.

The first thing you need to understand is this is NOT a library. It's a hardware package. Don't try to install hardware packages as a library. It doesn't work. You must install it following the instructions provided in the readme: https://github.com/esp8266/Arduino/#installing-with-boards-manager

The next thing you need to understand is that those instructions list multiple installation options. You should only choose one option. Don't install the package multiple times in multiple ways. For you, I recommend the "Installing with Boards Manager" instructions: https://github.com/esp8266/Arduino/#installing-with-boards-manager

Josephus: \Invalid library found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0: no headers files (.h) found in C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0

The solution to this is to delete C:\Users\sample\Documents\Arduino\libraries\esp8266-2.5.0. Since it's not a library, it's not doing you any good, and only causing annoying warnings. You already have the package installed multiple other times so you certainly don't need it here.

Josephus: i also noticed that there is a duplicate in the board list.

Since I don't know what you did to cause this, I can't give exact instructions for how to undo it. I assume you know what you did, so you can likely figure it out. My advice is to remove every installation of ESP8266 core for Arduino you did and then start fresh, following the instructions here exactly: https://github.com/esp8266/Arduino/#installing-with-boards-manager