Arduino Micro serial port disappears in Windows 7 device manager after reset

I am new at using the Arduino Micro R3 and have problems programming / uploading a sketch or using a sketch with serial communications. I read many postings but none solved my problem. (using Windows 7 64 - Arduino application 1.0.5)

The problem is that the serial port in windows "Device Manager" appears only for a few seconds after reset and then disappears. Device manager shows: Other devices > Arduino Micro The Hardware ID is: USB\VID_2341&PID_8037&REV_0100 USB\VID_2341&PID_8037

I can load a sketch by pressing reset on the board at the moment upload occurs. I used this step to upload the blink sketch with board type “Arduino Micro” set to ensure the Arduino Micro uses the correct device.

Also tried to update driver on the windows Device Manager > Other devices > Arduino Micro, and browse to C:\Program Files (x86)\Arduino\drivers Select "Next" The windows shows: "Windows was unable to install your Arduino Micro" "Windows could not find driver software for your device"

The arduino.inf (Arduino version 1.0.5 combined drivers) shows [DeviceList.NTamd64], USB\VID_2341&PID_0037, USB\VID_2341&PID_8037&MI_00

Not sure what I am missing to have the serial always present after reboot in device manager.

The Arduino Micro requires installation of two drivers. It has two different USB drivers, one for the bootloader and the other for the sketch core software. The bootloader driver will show up for a few seconds and disappear. But then the sketch USB driver should show up afterwards. Either you have a bad sketch loaded or the sketch USB driver did not install properly.

Check your Device Manager for any unknown USB devices and try and re-install it again.

If not then since the bootloader driver is still loading you can try and upload a new sketch from the IDE. From the IDE make sure you are selecting the Arduino Micro board type. Then select the example Blink sketch and upload. When the sketch compile is done you need to hit the reset button on the Micro and that should initiate the upload. It may be a little tricky on the timing when to hit that reset button, but just keep trying and hopefully you get it at the right time. This should put back on the proper sketch USB core driver and allow you to install it under Windows.

Thanks hiduino for the info.

Tried the above checks but no solution. Also I have no problems with the bootloader .

Using the reset step described above, I can load the sketch ok, but the serial still fails (Device manager shows: Other devices > Arduino Micro, expected serial COM in COM & LPT section). Also tried to load the blink sketch using board type Leonardo, but the same serial problem, in this case the Device manager shows: Other devices > Arduino Leonardo (as expected).

Discovered now that when the Micro is connected to USB 2.0 connector it works fine. The serial port appears and stays on. Also my Arduino UNO R3 works fine on this USB 3.0 connector port.

Info: Using Asus mother board 8Z68-V PRO/Gen3 with intel Z68 chipset and Intel 6 Series/C200 Series Chipset The USB 3.0 interfaces use the ASMedia Technologies driver.(latest drivers installed).

Provided more info on the Device manager "hardware ID" to compare between USB2 and USB3 connector. (loaded the blink program with board type “Arduino Micro”) On usb3 connector it fails. Hardware ID: Device manager shows: Other devices > Arduino Micro USB\VID_2341&PID_8037&REV_0100 USB\VID_2341&PID_8037 On usb2 connector it is ok. Hardware ID: Device manager shows: Ports (COM & LTP) > Arduino Micro (COM6) USB\VID_2341&PID_8037&REV_0100&MI_00 USB\VID_2341&PID_8037&MI_00

As this point it seems to point to a Arduino Micro driver issue when using USB 3.0 port connector. (Uno Rev 3 works fine in usb 3.0 - uses the ATMEGA16u2 for serial chip) (Arduino Micro R3 uses the MEGA32u4 chip).