i have solve this problem several times using the same steps :
1- Close Eclipse.
2- Restart your phone.
3- End adb.exe process in Task Manager (Windows). In Mac, force close in Activity Monitor.
4- Issue kill and start command in \platform-tools\
C:\sdk\platform-tools>adb kill-server
C:\sdk\platform-tools>adb start-server
5- If it says something like 'started successfully', you are good.
but now it's doesn't work cause i have an anti-virus called "Baidu", this program have run "Baidu ADB server", finally i turn this process off and retry above steps it's work properly.
