Compile for ESP8266 fails

I have a lot of sketches for the ESP8266 all working fine. Now I have a little test sketch that fails.

Processing esp12e (platform: espressif8266; board: esp12e; framework: arduino)
Verbose mode can be enabled via `-v, --verbose` option
PLATFORM: Espressif 8266 (2024.1.1) > Espressif ESP8266 ESP-12E
HARDWARE: ESP8266 80MHz, 80KB RAM, 4MB Flash
 - framework-arduinoespressif8266 @ 2.7.6 
 - tool-esptoolpy @ 1.40700.0 (4.7.0) 
 - toolchain-xtensa @ 2.40802.200502 (4.8.2)
LDF: Library Dependency Finder ->
LDF Modes: Finder ~ chain, Compatibility ~ soft
Found 28 compatible libraries
Scanning dependencies...
Dependency Graph
|-- DHT sensor library for ESPx @ 1.19.0
Building in release mode
*** [.pio/build/esp12e/firmware.elf] Implicit dependency `/Users/mk/.platformio/platforms/espressif8266/builder/=' not found, needed by target `.pio/build/esp12e/firmware.elf'.
============================================== [FAILED] Took 1.41 seconds ==============================================

platformio.ini starts the same as all others

platform = espressif8266
board = esp12e
framework = arduino
monitor_speed = 115200
lib_deps = 

Why can I compile more then a dozend programs partly huge successfull, but not a small one?

You have left the lib_deps empty.
Here you must specify the DHT library that you want to use.


lib_deps = markruys/DHT