Sometime some motor is suddenly on and the robot is out of control when the cortex is startting to run the joystick control program.
This situation did not always happen.
I use the version of 3.08.
I changed a new controller,the same thing happened again.
When I use easyc everything is ok.

Can you post your code so we can see if that is the source of the problem?

#pragma config(Sensor, dgtl1, bottom1, sensorTouch)
#pragma config(Sensor, dgtl2, bottom2, sensorTouch)
#pragma config(Sensor, dgtl3, up1, sensorTouch)
#pragma config(Sensor, dgtl4, up2, sensorTouch)
#pragma config(Motor, port1, leftup, tmotorVex393, openLoop, reversed)
#pragma config(Motor, port2, leftfront, tmotorServoContinuousRotation, openLoop, reversed)
#pragma config(Motor, port3, rightfront, tmotorServoContinuousRotation, openLoop)
#pragma config(Motor, port4, leftback, tmotorServoContinuousRotation, openLoop, reversed)
#pragma config(Motor, port5, rightback, tmotorServoContinuousRotation, openLoop)
#pragma config(Motor, port6, leftdown, tmotorVex393, openLoop, reversed)
#pragma config(Motor, port7, rightdown, tmotorVex393, openLoop)
#pragma config(Motor, port8, leftget, tmotorServoContinuousRotation, openLoop)
#pragma config(Motor, port9, rightget, tmotorServoContinuousRotation, openLoop, reversed)
#pragma config(Motor, port10, rightup, tmotorVex393, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard !!*//

char tdown=0;
char tup=0;
task main()
{

motor[leftget] = 50;
motor[rightget] = 50;
wait1Msec(200);

while (1==1) //Creates an infinite loop
{

motor[leftfront] = vexRT[Ch3] + vexRT[Ch4]; //y-axis value: forward/backward motion
motor[leftback] = vexRT[Ch3] + vexRT[Ch4];
motor[rightfront] = vexRT[Ch3] - vexRT[Ch4]; //x-axis value: left/right steering
motor[rightback] = vexRT[Ch3] - vexRT[Ch4];


tdown=0;
tup=0;
if ((SensorValue[up1]+SensorValue[up2])>=1) {tup=1;}
else {tup=0;}
if ((SensorValue[bottom1]+SensorValue[bottom2])>=1) {tdown=1;}
else {tdown=0;}

if (tup+tdown==0)
{
motor[leftup] = vexRT[Ch2];
motor[rightup] = vexRT[Ch2];
motor[leftdown] = vexRT[Ch2];
motor[rightdown] = vexRT[Ch2];
}
else if (tdown==1)
{
if(vexRT[Ch2]<20)
{
motor[leftup] = 0;
motor[rightup] = 0;
motor[leftdown] = 0;
motor[rightdown] = 0;
}
else
{
motor[leftup] = vexRT[Ch2];
motor[rightup] = vexRT[Ch2];
motor[leftdown] = vexRT[Ch2];
motor[rightdown] = vexRT[Ch2];
}
}
else if (tup==1)
{
if(vexRT[Ch2]>-20)
{
motor[leftup] = 0;
motor[rightup] = 0;
motor[leftdown] = 0;
motor[rightdown] = 0;
}
else
{
motor[leftup] = vexRT[Ch2];
motor[rightup] = vexRT[Ch2];
motor[leftdown] = vexRT[Ch2];
motor[rightdown] = vexRT[Ch2];
}
}


if(vexRT[Btn6U] == 1) //If button 5U is pressed:
{
motor[leftget] = 127; //run motor port 5 at quarter speed (i.e. lift an arm)
motor[rightget] = 127;
}
else if(vexRT[Btn6D] == 1) //If button 5D is pressed:
{
motor[leftget] = -127; //run motor port 5 at quarter speed reversed (i.e. lower an arm)
motor[rightget] = -127;
}
else //If neither buttons 5U or 5D are pressed:
{
motor[leftget] = 0;
motor[rightget] = 0; //stop motor port 5 (i.e. don't move arm up or down)
}

}//while
}

Can you describe precisely what problem you're having? What do you expect to happen, and what actually happens? Which motors are running out of control? When does this happen?

Before the program runs while() statement,the program can control the motor rightly.
when the while() statements begin to execute, maybe some of the four motors(leftup,rightup,leftdown,rightdown)is on immediately and I do not touch the joystick. By the way the motor's direction do not chang.It always lift up the arm.
I try to unplug the four motors and restart the cortex and the joystick,another two motor may begin to start.
This damaged some green motor protections.
Sometimes it just works fine.

Next time you post some code, please place it in tags to preserve indentation and make it easier to read. Otherwise, it makes it difficult to see which curly braces affect what. I've done it for you here, and maybe you or a mod can come and fix it for you up there:

It's a little hard to follow your code, as it's a little redundant. If you keep writing the same thing (setting all motors to ch2, or zero in your case), there's a good chance that there is a better way to do it. Take a look at this code, and tell me if it does what you want it to do. If so, try it out and see if it still produces the same problems. (I'm not responsible if this code damages your robot):

Thank you !
let me make more tests.