For some reason, my Arduino program has disappeared from my computer, and it was a really long, complex program. It is currently still on my arduino, and I HAVE to get it back. Please, someone help me. Arduino UNO, Macbook Pro.

Edit: Perhaps I wasn't clear. I need the INO file back FROM MY ARDUINO.

  • 1
    Time to fire up your undelete program... Commented Jan 14, 2015 at 21:34
  • Lesson learned: perform backups...
    – jfpoilpret
    Commented Jan 14, 2015 at 21:55
  • 1
    Your edit changes nothing. The .ino file is not on the Arduino. Commented Jan 14, 2015 at 21:56
  • 1
    To be specific, the .ino/.pde/.cpp/.h source code is not in the Arduino. But a working binary built from it us, which can normally be copied off and flashed to other devices. In some cases that might help, but it's a pain to modify or reverse engineer. Commented Jan 15, 2015 at 2:40
  • Perhaps a trip around Macbook advice on undeleting files would be more fruitful? "Ask Different" maybe? Does foremost work on MacBook? Commented Jan 15, 2015 at 13:43

2 Answers 2


The .ino file is lost, however, your Arduino IDE uses your %temp% to store immediate data.

Look in %temp%, folders akin to build116193871148509168.tmp contain build files. The original ino is not there, but I remember the cpp files generated by IDE should be there.

Some info about how to find the temp on Mac: https://stackoverflow.com/questions/11607834/where-are-the-hex-files-compiled-by-arduino

  • I am on mac, so I went to /tmp, but no cpp files were there. Thanks for trying to help, though. Commented Jan 14, 2015 at 22:12
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    Surprisingly, when i look in my folders, the cpp is not always there. But when i searched for <myinofilename>.cpp it found some. Dunno when the postprocessed cpp is stored there.
    – Bartosz
    Commented Jan 14, 2015 at 22:27
  • stackoverflow.com/questions/11607834/…
    – Bartosz
    Commented Jan 15, 2015 at 8:28

Your INO file is not (ever) on your Arduino.

When you "upload your sketch" to the Arduino, it is first compiled. Your Arduino cannot interpret a sketch directly, and there are various processes which convert your sketch into machine code. This process is not practically reversible.

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