Side note:
While making a mission, if you inadvertenly use an object from an addon and later remove it, your mission will still have the dependency on the addon. So it can be easy to forget and publish the mission not knowing you have the dependency. So its a good practice to look at your mission.sqm file under the addons section:
class Mission
{
addOns[]=
{
"cacharacters",
"map_misc",
"desert",
"CATracked"
};
addOnsAuto[]=
{
"cacharacters",
"CATracked",
"map_misc",
"desert"
};
The above mission uses one addon "map_misc" from MapFAct. To remove this addon, I would delete the two entries for "map_misc" and save the mission.sqm file. This mission would then be free of addons.
f you aren't familiar with the original game addons, it may be hard to spot what is an external addon...