ESP8266 - cannot upload to SPIFFS

First time trying to use SPIFFS and got problem - cannot perform SPIFFFS upload from Tools menu.

(link)

PC: Windows 10, Arduino 1.8.11, for other projects works perfectly.
Plugin is from here: Release Add support for python 3 for Arduino-ESP8266 2.6.x · esp8266/arduino-esp8266fs-plugin · GitHub

What is the problem? Should I really install Python?

SergeS:
First time trying to use SPIFFS and got problem - cannot perform SPIFFFS upload from Tools menu.

(link)

PC: Windows 10, Arduino 1.8.11, for other projects works perfectly.
Plugin is from here: Release Add support for python 3 for Arduino-ESP8266 2.6.x · esp8266/arduino-esp8266fs-plugin · GitHub

What is the problem? Should I really install Python?

Got it fixed...
I have copied esp8266fs.jar into two locations:

  1. C:\Program Files (x86)\Arduino\tools\ESP8266FS\tool
    and
  2. C:\Users\Serge\Documents\Arduino\tools\ESP8266FS\tool
    which was wrong!

Correct location is: \tools\ESP8266FS\tool\

I had old esp8266fs.jar there, have replaced it and upload works now.