Pro Micro 5V - Not Recognized after Upload

Dear Sparkfun,

I have enjoyed many of your products and have had lots of success in using them. However, I have recently been integrating a Pro Micro 5V (https://www.sparkfun.com/products/12640) in one of my newest projects with unfortunate results. I connected the Pro Micro to my computer to program it, chose the port and board in my Arduino IDE and installed my sketch. The board began to allow the install then my computer notified me that the USB device was now not recognized. I was worried that it was possibly my cable and tried another to no avail. I then attached a new Pro Micro and the same thing happened…

After much troubleshooting, I discovered that there was another dropdown option in the IDE (that I have never had to use with any of my previous boards) in order to choose between the type of the Pro Micro - it was defaulted at 3V. I selected the 5V option and [reluctantly] uploaded to a third Pro Micro and it worked. Yet, the first two Pro Micro boards are still unrecognized by my computer.

What I’d like to know is if both of my $20 Pro Micro boards have been damaged by this unassuming error? If they have, I am very disappointed that this can happen so easily and from within the Arduino IDE. If there is hope for them, please let me know how to remedy since I need to get my project up and running.

Thanks in advance for your time.

Hi,

This is a very common error with the Pro Micro and boards like it that handle the USB-to-Serial conversion inside the IC. You can reset to the bootloader by following the instructions in the [Troubleshooting and FAQ section of the Hookup Guide. It takes a few tries since it only remains in bootloader mode for 8 seconds but that will recover the boards.](https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide#troubleshooting-and-faq)