Is there no more output? There should be something like
Reading symbols from C:\Users\Max\Documents\PlatformIO\Projects\attiny\.pio\build\uno\firmware.elf...
done.
PlatformIO Unified Debugger -> http://bit.ly/pio-debug
PlatformIO: debug_tool = avr-stub
PlatformIO: Initializing remote target...
0x0000033a in micros () at C:\Users\Max\.platformio\packages\framework-arduino-avr\cores\arduino/wiring.c:103
and possible error messages.
My example still works fine for me, so I can’t reproduce the error you’re getting.
You could also try the suggestion in Cannot debug STM32: "Failed to launch GDB: Error: write EPIPE" - #4 by maxgerhardt or blatantly re-installing PlatformIO (remove all system-installed PlatformIO cores ever installed, especially if done globally via pip, remove C:\Users\<user>\.platformio\ completely, remove VSCode PlatformIO extension, then reinstall it and retry).
Also sometimes antivirus software can interfer with it, you might want to temporarily disable it.