EDIT: After doing some more digging, I found [url=https://forum.arduino.cc/index.php?topic=634830.0]this[/url] thread, which says to delete the files in your arduino15 folder. Here [url=https://forum.arduino.cc/index.php?action=profile;u=224903]pert's[/url] fix:
This error indicates you need to take some drastic action. Be aware this is somewhat advanced and will remove any boards you have installed via Boards Manager:
In the Arduino IDE, 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.
Delete all files and folders under the Arduino15 folder except for preferences.txt. Please be very careful when deleting things from your computer. When in doubt, back up!
Restart the Arduino IDEVerify that you can now use your board before reinstalling any packages via Boards Manager.
This solved the issue perfectly, and I hope this helps anybody in the future.
Original Post:
I get this error whenever I try to compile a sketch. The verbose output is below.
I have a theory on why an error might have occurred, but I have no idea how to fix it, and I have never run into this before. Right before the error started happening, the whole Arduino program would not open. Finally, I was able to get it to load (I don't remember exactly what I did but I opened an executable.) I uploaded my program to the wrong port and so it was taking forever to compile (This could be an issue, in the past when I uploaded something to the wrong port it wouldn't upload) and I clicked on a pop up message that said that I had updates for my boards. I then downloaded the board updates while the program was still compiling. Here is the verbose output of the error, with every username replaced with (name):
Arduino: 1.8.10 (Mac OS X), Board: "Arduino Nano, ATmega328P"
/Applications/Arduino.app/Contents/Java/arduino-builder -dump-prefs -logger=machine -hardware /Applications/Arduino.app/Contents/Java/hardware -hardware /Users/(name)/Library/Arduino15/packages -tools /Applications/Arduino.app/Contents/Java/tools-builder -tools /Applications/Arduino.app/Contents/Java/hardware/tools/avr -tools /Users/(name)/Library/Arduino15/packages -built-in-libraries /Applications/Arduino.app/Contents/Java/libraries -libraries /Users/(name)/Documents/Arduino/libraries -fqbn=arduino:avr:nano:cpu=atmega328 -vid-pid=0403_6001 -ide-version=10810 -build-path /var/folders/cl/n5p832bs5sq1l63bx6tdfxt00000gn/T/arduino_build_774559 -warnings=none -build-cache /var/folders/cl/n5p832bs5sq1l63bx6tdfxt00000gn/T/arduino_cache_504313 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avr-gcc.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5 -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino5.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5 -prefs=runtime.tools.avrdude.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17 -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17 -prefs=runtime.tools.arduinoOTA.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/arduinoOTA/1.3.0 -prefs=runtime.tools.arduinoOTA-1.3.0.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/arduinoOTA/1.3.0 -verbose /Users/(name)/Desktop/AE Modular/AE Modular Custom Modules/Mini Midi Keyboard/Mini_Midi_Code_for_Nano_bad_part_2/Mini_Midi_Code_for_Nano_bad_part_2.ino
/Applications/Arduino.app/Contents/Java/arduino-builder -compile -logger=machine -hardware /Applications/Arduino.app/Contents/Java/hardware -hardware /Users/(name)/Library/Arduino15/packages -tools /Applications/Arduino.app/Contents/Java/tools-builder -tools /Applications/Arduino.app/Contents/Java/hardware/tools/avr -tools /Users/(name)/Library/Arduino15/packages -built-in-libraries /Applications/Arduino.app/Contents/Java/libraries -libraries /Users/(name)/Documents/Arduino/libraries -fqbn=arduino:avr:nano:cpu=atmega328 -vid-pid=0403_6001 -ide-version=10810 -build-path /var/folders/cl/n5p832bs5sq1l63bx6tdfxt00000gn/T/arduino_build_774559 -warnings=none -build-cache /var/folders/cl/n5p832bs5sq1l63bx6tdfxt00000gn/T/arduino_cache_504313 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avr-gcc.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5 -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino5.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5 -prefs=runtime.tools.avrdude.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17 -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/avrdude/6.3.0-arduino17 -prefs=runtime.tools.arduinoOTA.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/arduinoOTA/1.3.0 -prefs=runtime.tools.arduinoOTA-1.3.0.path=/Users/(name)/Library/Arduino15/packages/arduino/tools/arduinoOTA/1.3.0 -verbose /Users/(name)/Desktop/AE Modular/AE Modular Custom Modules/Mini Midi Keyboard/Mini_Midi_Code_for_Nano_bad_part_2/Mini_Midi_Code_for_Nano_bad_part_2.ino
Using board 'nano' from platform in folder: /Users/(name)/Library/Arduino15/packages/arduino/hardware/avr/1.8.1
Using core 'arduino' from platform in folder: /Users/(name)/Library/Arduino15/packages/arduino/hardware/avr/1.8.1
Detecting libraries used...
/Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/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=10810 -DARDUINO_AVR_NANO -DARDUINO_ARCH_AVR -I/Users/(name)/Library/Arduino15/packages/arduino/hardware/avr/1.8.1/cores/arduino -I/Users/(name)/Library/Arduino15/packages/arduino/hardware/avr/1.8.1/variants/eightanaloginputs /var/folders/cl/n5p832bs5sq1l63bx6tdfxt00000gn/T/arduino_build_774559/sketch/Mini_Midi_Code_for_Nano_bad_part_2.ino.cpp -o /dev/null
fork/exec /Users/(name)/Library/Arduino15/packages/arduino/tools/avr-gcc/7.3.0-atmel3.6.1-arduino5/bin/avr-g++: no such file or directory
Error compiling for board Arduino Nano.
(Sorry for the wall of code, I tried putting it in code tags but it just added a really long sideways scrollbar.)