To reset addons in a mission I open the mission.sqm file and edit the front bit.
It normally looks like this;
version=11;
class Mission
{
addOns[]=
{
"bas_soar185",
"Flags1",
"Su25",
"6G30",
"Nimitz",
"LaserGuided",
"AH64",
"editorupdate102"
};
addOnsAuto[]=
{
"bas_soar185",
"Flags1",
"Su25",
"6G30",
"Nimitz",
"AH64",
"editorupdate102"
};
but I simple change it to this, save it, then open up the mission for editting in OFP and it usually fixes most problems.
version=11;
class Mission
{
addOns[]=
{
};
addOnsAuto[]=
{
};
Suggest copying the file beforehand ..... just in case.