I reinstalled Windows 7 last week and unzipped Eclipse and reinstalled the SDK again, but I didn't run the program in Eclipse. When I connect the Galaxy phone to my computer, Eclipse shows an error and frequently writes in the console tab Failed to start monitoring 0A3C202B1601A00A. After a while, Eclipse qill show an Android Device Chooser window. I can't select 0A3C202B1601A00A.
I use ADB and i write adb address and adb devices in cmd, cmd writes deamon not running.
When I disconnect the phone from my computer and I want to run the program with an emulator, the program won't run and when I write adb devices in cmd, cmd nothing written.
Why? Please help me :(
Kill the adb task via task manager. Then, type at the command prompt: adb devices
This should restart the adb daemon and all is well.
Re-install the windows driver for your galaxy phone. Its possible that it is corrupted. I had to re-install mine just to get the OS to detect my phone a while back.
Also check the USB debugging mode the phone is using. Sometimes the phone can go into a storage-only mode.
来源：https://stackoverflow.com/questions/12980767/failed-to-start-monitoring-and-not-run-the-program-why