I added one serial.println(FILE); line to my sketch that compiled and downloaded successfully before and get the following error as soon as I click Verify:
"processing.app.debug.RunnerException
at cc.arduino.Compiler.callArduinoBuilder(Compiler.java:317)
at cc.arduino.Compiler.loadPreferences(Compiler.java:216)
at cc.arduino.Compiler.build(Compiler.java:175)
at processing.app.SketchController.build(SketchController.java:664)
at processing.app.Editor$BuildHandler.run(Editor.java:1632)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: Cannot run program "C:\Program Files (x86)\Arduino\arduino-builder": CreateProcess error=2, The system cannot find the file specified
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
at processing.app.helpers.ProcessUtils.exec(ProcessUtils.java:26)
at cc.arduino.Compiler.callArduinoBuilder(Compiler.java:297)
... 5 more
Caused by: java.io.IOException: CreateProcess error=2, The system cannot find the file specified
at java.lang.ProcessImpl.create(Native Method)
at java.lang.ProcessImpl.(ProcessImpl.java:386)
at java.lang.ProcessImpl.start(ProcessImpl.java:137)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
... 7 more "
I am running Arduino 1.8.13.
Somehow arduino-builder.exe had disappeared. I downloaded the latest nightly build .zip file and restored the .exe to the Arduino directory.