Leonardo not detected by computer [solved]

Hello everybody. I've been using a leonardo for a while without any problems, but today my computer stopped detecting the leonardo. I tried on multiple computers, but it won't show up in any of them. I don't hear the typical sound on windows when you connect a usb device. I already tried burning the bootloader again using an MKII, but no luck. The led on D13 blinks, but the leonardo doesn't show up on the computer and it doesn't seem to even try to communicate with the computer.

Does anybody know why this could be?

i have a similar problem, but in my case the tx led is always on, even if i reset it.
When i connect the leonardo, the pc detects it, but only in the bootloader, after that, the arduino is not connected any longer, i have more problem with this "Leonardo", but this is the bigger, i could upload code to the board sometimes, but now nothing.

Can anyone help us?


I'm in your boat as well. Exactly the same symptoms as "quetzalfir" described with all Micro Pro I have had:

When reset with "double click", "Device Manager" is able to recognize the board as "SparkFun Micro Pro", but after 8 sec Windows 8 is switching the board to "USB IO Board" in "Other Devices".

I tried to reinstall the driver - issue not resolved.

I can add couple of things:

(1) brand new board do not have this bad behavior. But after I uploaded any (even simplest "blink" sketch) to the board - the board is "catching" the issue.

(2) looks like board itself is working fine. I'm able to upload simple sketch to the board if "reset" after push of "upload" button in Arduino IDE (not each time, but if timing is good). When new sketch uploaded it is working fine (tested with different variations of "blink" example).

Please, help/advise.

Where did these Leonardos come from, and are you all using Windows 8?

In my case, from different sources: SparkFun and Ebay sellers. All boards of this type has had this issue. My Uno’s and Mega’s are working just fine. So, I think it isn’t “board” issue, but Windows 8 “driver”.

UPDATE: Checked on another PC with Windows 7 - all "SparkFun Micro Pro" boards are working better. I was able to upload sketch without an issue. Devices are recognizable all time by Device Manager. Only minor issue which is related to Arduino IDE - each time I reset the board, IDE is missing COM port which board connected to. So, I need disconnect the board and connect it again to have it available in the IDE.

Interesting. So on Windows 7 it works, on Windows 8 you need to power the Leonardo down after programming to see it again.


Hello everybody. I've been using a leonardo for a while without any problems, but today my computer stopped detecting the leonardo.

Depending on what sketch you have uploaded the Leonardo may not present a USB device to the computer. For example, to see a serial port, you need to have a sketch that does a Serial.begin() call.

sorry for haven’t responded, I already could fix the problem, I installed the Arduino 1.5.8 BETA IDE, and worked!!, I’m on Win8.
sometimes if you don’t upload the sketch in the correct way, you could need another PC with the same IDE and try to upload from there. and try several times, not many, but several times.

@quetzalfir is correct. I had a program with multiple tabs for the Leonardo in the Romeo V2.2. It worked when I had Arduino 1.5.8 BETA IDE. After the update my program would crash the microcontroller when trying to upload it. I end up buy 2 more Romeo V2.2 (Leonardo board) and a bootloader and couldn't fix the issue. The bootloader would bring them back but there was no way to upload the codes successfully. I tried different versions and it only works with Arduino 1.5.8 BETA IDE. I guess Leonardo and Arduino 1.5.8 BETA IDE should get married and never separate again.