oh i thought delete would delete the hole post sorry...

@James Higs find the mission folder this is normaly in documents/arma3/mpmissions or documents/arma3 other profiles/your arma 3 username/mpmissions then right click >new>text document and place one of the two codes below in the txt file save it then rename the New Text Document.txt to initServer.sqf make user you remove/rename the .txt to .sqf not .sqf.txt

    //initServer.sqf
    addMissionEventHandler ['HandleDisconnect',{deleteVehicle (_this select 0);}];

If you want a delayed delete, use this code below

    //initServer.sqf
    addMissionEventHandler ['HandleDisconnect',{
    [(_this select 0)] spawn {
	sleep 10;
	deleteVehicle (_this select 0);
    };
    }];

*as stated above this has not been tested by myself but has by users on orignal thread linked in other comment.

he found this on BI forums reported as working by muitlpe sources untedted by my self just copy pasted hope it works.

example:

    //initServer.sqf
    addMissionEventHandler ['HandleDisconnect',{deleteVehicle (_this select 0);}];

If you want a delayed delete, something like this will work:

    //initServer.sqf
    addMissionEventHandler ['HandleDisconnect',{
    [(_this select 0)] spawn {
	sleep 10;
	deleteVehicle (_this select 0);
    };
    }];

* Run on server only as per linked instructions
Further reading for those interested:
http://feedback.arma3.com/view.php?id=17532

*source fn_Quiksilver @ BI forums https://goo.gl/HMNxiK

Sorry @HeroesandvillainsOS bad wording more updated so that it does not require all the _this addAction it maybe its just an easier way of doing it sorry for the confusion. I remember having issues with _this addAction ["Open Virtual Arsenal", {["Open",true] spawn BIS_fnc_arsenal}]; after a few mis searching i used the ["AmmoboxInit",[this,true]] call BIS_fnc_arsenal;

No only in local MP testing not dedi 2 Aresenal options still appear on editor placed boxes but i think i'm on the correct path.
My arma knowledge is no where near you guys but i know alot of other code. I know at some point _this addAction ["Open Virtual Arsenal", {["Open",true] spawn BIS_fnc_arsenal}]; was replaced now in the box init you just need ["AmmoboxInit",[this,true]] call BIS_fnc_arsenal; so i assume the reason the code is repeating is because _this; _crate addAction ["<t color='#ff1111'>BIS Arsenal</t>", {["Open",true] call BIS_fnc_arsenal}]; its adding an addAction with the arsenal code and just the ["AmmoboxInit",[this,true]] call BIS_fnc_arsenal; part is adding it a second time.

So would it work like this

_crate = _this;
[-1, {
    _crate = _this; _crate [{["Open",true] call BIS_fnc_arsenal}];
}, _crate] call CBA_fnc_globalExecute;

or this

description.ext...

class Extended_Init_EventHandlers {
     class B_supplyCrate_F {
		init = " _this call (compile preprocessFileLineNumbers '["AmmoboxInit",[this,true]] call BIS_fnc_arsenal;')";
     };
};

*updated 29/01/17 Ok so ive tested bot the above and they don't work still getting 2 Arsenal options on editor placed boxes i've just changed the box wired error thanks for the initial help.

**edited got abit ahead of my self there its ok testing localy mp but seems to sill happen on dedicated wired ill just use a different box thx for the help

hello there i used the following to create Arsenal on airdrop but on dedicated the Arsenal option repeats itself 2 arsenal options in the drop down this only occurs on editor placed boxes the droped ones are fine any idea why this is happening the init line of the editor placed box is empty.

description.ext...

class Extended_Init_EventHandlers {
     class B_supplyCrate_F {
		init = " _this call (compile preprocessFileLineNumbers 'arsenalCrate.sqf')";
     };
};

arsenalCrate.sqf...

_crate = _this;
[-1, {
    _crate = _this; _crate addAction ["<t color='#ff1111'>BIS Arsenal</t>", {["Open",true] call BIS_fnc_arsenal}];
}, _crate] call CBA_fnc_globalExecute;

thx in advanced for any help and an amazing commuinty/mod

seriously friendly and helpful community thank you for helping. please close or delete thread.

All fixed now thx for the help. It was an issue with server the servers running fine just having issues with C2ISTAR auto missions not succeeding. I am using OP land lord the broken un-succeeded mission also will not delete. but I am currently creating a costume mission to see if this resolves the issue although it seems to be an issue after the a3/cba update

ohhh ok seems im just being a idiot was trying to upload both the dll and .so files to the server and yer im just running the @aliveserver on the dedi
ty for the response