| this happens when you run other softwares that use adb in background, when im running chimera tool for example i get the error but as soon as i close chimera and restart gc pro gsm tool it works fine.
other known programs that use adb in backgroud are root tools like king or kingo root, and last some phone brand related tools such as HTC sync manager may also be using adb.
check and close or uninstall those other adb programs and gc will work fine |