I am also having a problem with Arduino 1.67 and also 1.68
Using ESP8266 stable release 2.1
When I try to compile I get the following error:
Arduino: 1.6.7 (Windows 10), Board: "NodeMCU 1.0 (ESP-12E Module), 80 MHz, Serial, 115200, 4M (3M SPIFFS)"
Board nodemcuv2 (platform esp8266, package esp8266) is unknown
Same with any board
Has anyone else had this problem and fixed it?
Oldmicroguy