In case you're the Squad leader:

Select every unit you want to cease firing with F1-F12 buttons and press 7. It should open a menu with commands like stealth, safe, danger and aware.
Select stealth and your squadmates will cease their fire and avoid engaging any targets they see. They will also seem to move more by crouching and sometimes go to prone.
If you want them to fire, just point them at the target and say open fire (which doesn't remove the stealth mode) OR just switch mode off by selecting danger, safe or aware.
All modes have different effects to A.I. I suggest that you try them out.

voted up. AI has overpowers in stuff like spotting, aiming and has no freightness of being shot or taking cover,lol

Ummm... Tell them to Hold Fire... As for engaging MRAP's with assault rifles... Well that needs fixing...

but it is true the AI will start shooting at something anyone but a marksman would consider to far away and when you leave Danger to a different behavior the chances of your men slipping up goes up ive often had my men go in to Aware mode or Stealth just to have them get shot up because they took a corner without looking or they stood up while under fire and moved somewhere like they wernt being shot at all tactical and what not or my men wont be scanning the area and moving as slowly because theyre not in combat mode so they will miss targets down allys or hanging out between a building and something else and ill end up in the middle of an enemy base with me and an entire team to draw attension and the enemy will start firing all at once as soon as i get within a certant range and imediately 15 people are shooting at me and my squad is dead

The real issue is that the friendly AI squad members do not properly follow your oders...even if you tell them to "hold fire", most of the time they will break that command and still fire upon sighted enemies. It has been left neglected this way for years.

Simply order your AI team to hold fire. It is really all about being a good team leader and controlling the AI properly, ArmA does not use so many key's for nothing. I hope BIS will releas a tutorial video showing how to command an AI team properly, because a lot of new players don't have a clue.

And if an AI unit does not 'hold fire' when ordered then the AI 'thinks' that he is in immediate danger and will open fire to protect himself (thats the idea anyway).

@Bootsy - it is a broken feature that requires constant baby sitting should you decide to use it...read what I posted....and please don't reply back saying they'll only break the command if they're fired upon by enemy because that is simply not so...they will often break the hold fire command even when the enemy has not yet spotted you or your group members.

I can only say that I rarely (not often anyway) have AI team units opening fire unless I order them to (but yes it happens sometimes). That probably also has something to do with how I position the AI units, I try to make sure they stay out of direct danger unless I want them to. Do you also use the order 'no target' by the way?

Regarding the 'no target" command, not really...mostly because to use that requires you to have visual contact on the 1 enemy unit out of a group of many and typically my AI group members have the ability to spot things nearly a kilometer away (long before I ever see them). For me it's just alot quicker & easier to use the "no fire" command when I am trying to be stealthy.

As far as the "hold fire'...my only guess at a possible reason for you success in using it would be that perhaps you are keeping your AI out of direct line of sight with the enemy so that even though they might know the enemy is there they do not have direct line of site to fire anyway....but this does not mean the "hold fire" command functions properly...in fact it can't be considered a valid test method at all in this case.

The AI should be put into direct line of site and still be able to hold fire if that's what you are commanding them to do...and more often than not, the result is not a good one, hehe. Some of my group will obey but there's always at least 1 of the group who will break the command and begin firing...this should not be and makes the command next to useless.

There's also been a huge bug during "danger mode" where they often will not respond to commands, but that's another bone to pick i suppose.

Sometimes I just cant help but feel alot of this feedback falls on deaf ears anyway since these are well known issues that have been around for extreme lengths of time, left untouched...meanwhile it's easier for them to fix which direction the fish are swimming, lol.

Duplicate of #6513