So, this is what I am doing. Connecting Arduino Leonardo to my Laptop. It gets detected in device manager. (I have updated the driver as well). However I soon hear a beep and Leonardo gets uninstalled. If I push 'Reset' button it gets detected again however after a few seconds it gets disconnected again. The device manager displays the following message - "Currently, this hardware device is not connected to the computer. (Code 45)". Please help.

Note: It was working fine couple of weeks back

I am using Windows 7

  • \$\begingroup\$ who or what is Leonardo? I can think of at least 3 different products that had Leonardo in their names associated with EE. You'll have to be a little more specific. \$\endgroup\$ May 4, 2013 at 19:35
  • \$\begingroup\$ Arduino Leonardo. \$\endgroup\$
    – alps
    May 4, 2013 at 19:59
  • \$\begingroup\$ Do you connect just the Arduino board or do you also have some other components attached? The laptop may be disconnecting the USB device if it tries to pull too much current (>500mA) \$\endgroup\$
    – DimKo
    May 4, 2013 at 20:20
  • \$\begingroup\$ only the Arduino Board. \$\endgroup\$
    – alps
    May 4, 2013 at 20:23
  • 1
    \$\begingroup\$ @rawbrawb The other two are Donatello and Rafael \$\endgroup\$ May 4, 2013 at 20:29

1 Answer 1


I have had similar issues, and found that if you have external power to the Arduino, it can cause strange USB behavior. I also noticed if you press the reset button, you need to fully power cycle the device, and run only off USB power before the serial connection will be usable.

Whenever I prototype with mine, I put an on-off switch on the breadboard to easily disconnect from external power.

That being said, I don't know if this question belongs in the 'Electrical Engineering' Q & A. I don't know a better spot though :-)

  • \$\begingroup\$ I am not using external power supply. Hope someone has a suggestion here :-) \$\endgroup\$
    – alps
    May 4, 2013 at 20:23
  • \$\begingroup\$ And the reset button? Make sure you power down completely after pressing the button or it won't initialize correctly. \$\endgroup\$
    – Butters
    May 4, 2013 at 22:31
  • \$\begingroup\$ I did, but still no luck. \$\endgroup\$
    – alps
    May 5, 2013 at 20:33
  • \$\begingroup\$ Hmmm... How about a different USB port on the computer? Keep in mind this will result in your device getting a different COM port assigned to it. \$\endgroup\$
    – Butters
    May 5, 2013 at 20:35
  • \$\begingroup\$ Was finally able to solve the issue by using the Leonardo on my desktop with Windows xp \$\endgroup\$
    – alps
    Jun 1, 2013 at 11:38

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