Boards. Manager

I upgraded to ESP8266 2.4.2, as prompted by Arduino IDE. This changed the naming of Wemos D1 Mini to LOLIN Wemos D1 Mini, and now the IDE will not recognize the board. The error message is:

Arduino: 1.8.5 (Mac OS X), Board: "WeMos D1 R2 & mini, 80 MHz, 921600, 4M (1M SPIFFS)"

Board d1_mini (platform esp8266, package esp8266) is unknown

Error compiling for board WeMos D1 R2 & mini.

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

I tried rolling back to an earlier version of ESP8266, but the error persists.

How do I find the bad file on MacOS?

Can this bug be fixed?



The "Board ... is unknown" error occurs when a Boards Manager installation of a different version of a hardware package fails to completely uninstall the previous version. Here's how you solve it:

  • Click the link on the line following File > Preferences > More preferences can be edited directly in the file. This will open the Arduino15 (or similar name depending on OS) folder.
  • Navigate to the packages/esp8266/hardware/esp8266 folder.
  • You will see two folders. One is named by the version of the package you currently have installed, the other is named by the version of the package you previously had installed. Delete the folder with the previous version name. Please be very careful when deleting things on your computer. When in doubt back up!