Arduino IDE won't upload sketches

Question

I recently updated my Arduino IDE to 1.8.5 from 1.6.9. I am getting issues with uploading sketches. The sketch compiles, but when I try to upload it I get this message:

Arduino: 1.8.5 (Mac OS X), Board: "Arduino/Genuino Mega or Mega 2560, 
ATmega2560 (Mega 2560)"

Sketch uses 642 bytes (0%) of program storage space. Maximum is 253952 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 8183 bytes for local variables. Maximum is 8192 bytes.
java.io.IOException: Cannot run program "___REMOVE___/bin/avrdude": error=2, No such file or directory
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1048)
    at java.lang.Runtime.exec(Runtime.java:620)
    at java.lang.Runtime.exec(Runtime.java:485)
    at processing.app.helpers.ProcessUtils.exec(ProcessUtils.java:11)
    at cc.arduino.packages.Uploader.executeUploadCommand(Uploader.java:129)
    at cc.arduino.packages.uploaders.SerialUploader.uploadUsingPreferences(SerialUploader.java:207)
    at cc.arduino.UploaderUtils.upload(UploaderUtils.java:78)
    at processing.app.SketchController.upload(SketchController.java:713)
    at processing.app.SketchController.exportApplet(SketchController.java:686)
    at processing.app.Editor$DefaultExportHandler.run(Editor.java:2168)
    at java.lang.Thread.run(Thread.java:748)
Caused by: java.io.IOException: error=2, No such file or directory
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:247)
    at java.lang.ProcessImpl.start(ProcessImpl.java:134)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1029)
    ... 10 more
An error occurred while uploading the sketch

This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.

I get this message whether or not an Arduino is connected. I also get the same message weather I connect my Arduino Mega or Uno. I tried my sketch, the blink sketch and a completely blank sketch, all with the same results.

Could I please get some help with this issue?

Answer 1

You may be able to fix this by taking some drastic action. Be aware this is somewhat advanced and will remove any boards you have installed via Boards Manager:

1. 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.
2. 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!
3. Restart the Arduino IDE.
4. Verify you can now upload before re-installing any boards via Boards Manager.