FQBN: arduino:avr:uno
Using board 'uno' from platform in folder: C:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\hardware\avr\1.8.6
Using core 'arduino' from platform in folder: C:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\hardware\avr\1.8.6
Detecting libraries used...
C:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++ -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10607 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR -IC:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino -IC:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard C:\###\mixly2.0-win32-x64一键更新版\mixlyBuild\sketch\testArduino.ino.cpp -o nul
Alternatives for SoftI2CMaster.h: []
ResolveLibrary(SoftI2CMaster.h)
-> candidates: []
C:\###\mixly2.0-win32-x64一键更新版\testArduino\testArduino.ino:2:10: fatal error: SoftI2CMaster.h: No such file or directory
compilation terminated.
Error during build: exit status 1
Used platform Version Path
arduino:avr 1.8.6 C:\###\mixly2.0-win32-x64一键更新版\arduino-cli\Arduino15\packages\arduino\hardware\avr\1.8.6
==编译失败==

把mixly文件夹放在D盘，或者其他什么盘的根目录下，例如D/mixly.......这样，目录中不能有中文