esp8266 IDE install fialed, "file signature verification failed. File ignored."

Hi ,
I want to use esp8266 board by arduino IDE ,but i can't get the esp8266 board information from Boards Manager
When i open Boards Manager , the follow alert appear.
" file signature verification failed. File ignored."
How can I solve this problem. Please help me!

  • Close the Arduino IDE's Boards Manager window if it's open.
  • Click the link at the line following File > Preferences > More preferences can be edited directly in the file. This will open a folder on your computer named Arduino15 (or similar depending on which OS you're using).
  • From that folder, delete all files that start with "package_esp8266com_index".
  • Try installing the ESP8266 core for Arduino via Boards Manager again.

Hopefully deleting those files will fix the issue.