Mass Effect 2

Use incinerate on your enemies armour (their health bar will be yellow if their current defence is armour)

You can do this either with your character or by ORDERING a squad mate to use there power on the enemy. It will not count if the squad mate uses it without you ordering them, go into options menu and turn off squad mate power usage so they don't use their powers automatically.

Also, when the power is activated it must completely rip off the enemy armor, if theres any armor left on enemy then it will not count.. On easy you wont have this issue!! However on harder difficulties the power may not completely rip off the enemy armor, best bet would be to weaken the armor some what then use the power.. Or use the power more then once as it recharges. (Thanks Solario32)

Once you find a squad of enemies such as Krogans that have armour use the power then reload your save and do it again to get it quicker.

I did It on the recruiting Grunt mission, When you enter the compound you will fight quite a few Krogan right away with armour, Using the Salarian squad mate's (Mordin) incineration power on all of them, Then reloaded the auto save till I got achievement.

Side Note: Incendiary ammo will NOT work for this achievement.. It must be the incendiary power that can be accessed and used through Mordin!

Side Note 2: If you wan't this power for your character you will need to build an infiltrator or engineer class

If your class does not have the ability "Incinerate", just use Mordin. He has that power, if he does it on his own it does not count. Also, destroying armor with incinerated ammo does not count toward this achievement. Short and sweet.

If you do not want to seek out armored enemies or if you missed the final level opportunity, you can just start a new game and choose the Engineer class. This gives you the Incinerate ability (which you will need to burn the armour), and if you import a level 55+ character from the first Mass Effect you can put some points into Incinerate to power it up. Set the difficulty to Insanity and all the mechs that you fight will have armor. On the easier difficulties, mechs do not have armour, so you must put it on Insanity. There is also less of a chance of having your allies kill them before you can use Incinerate.

It's better to try this during the second mission, "Freedom's Progress," because you won't get overwhelmed as easily. There are 6 mechs in the first encounter. Just save in front of the first large door you come to and keep reloading when you kill them all or die (you will probably die). There is also an auto-save just before the encounter, so if you forget to save, you're still covered and you can just reload from there.

NOTE: It is already mentioned in the other guides, but allies who use Incinerate on their own will NOT count towards the achievement. Simply set "Squad Power Usage" to "Disabled" in the options menu. Also, if you deal damage to the enemy's armour before you use Incinerate, it WILL still count towards the achievement, so don't worry if you or an ally shoots them first, as long as you use Incinerate to take out all of the remaining armour.

ALSO NOTE: You must use Incinerate to burn the enemy's armour completely. What I mean is, you can shoot them first to weaken their armour, but when you use Incinerate it must destroy all of their remaining armour so that only their health remains. If they still have armour left, it will not count, unless you use Incinerate again (you or an ally who has been commanded to do it) to burn the rest.

If like me by the time you'd reached the suicide mission and you still didnt have this achievement (or the warp specialist achievement) then the suicide mission is very easy to get it on.

Just play through the level always taking both Miranda and Mordin with you as they together have incinerate, warp and overload. With each group of collectors you encounter throughout the mission one of them will be possessed and gain armour and a barrier, a very good way to boost here is to focus on that possessed collector because once he is killed another will be possessed also giving them armour and a barrier.

Simply rinse and repeat and it should be yours fairly easily.

I Yova I's solution was very helpful in this but there are a couple of things I wanted to add, but I'd too stick with doing it on the Suicide Mission. If you're going for No One Left Behind achievement (No one dies on the Suicide Mission) save the game at the 8th valve on the initial part of the attack on the Collector Base. When you press it you dont get another chance to save the game before taking your squad through the biotic phase and in order to ensure you complete No One Left Behind, it's best to send Moridin back to the ship, as he seems to have a horrible habbit of getting himself killed at every opportunity, but you miss the chance to use his incineration if you send him back, so it's best to keep a save there, go on and complete the game and then reload when you're back on the Normandy and have a post-game save.

When you've reloaded, hit the 8th valve again and when you're through the video clips take Moridin with you (and Miranda if you want the Warp Specialist too). When you enter the next part you wont be able to save it as the walking parts count as combat, but when your chosen biotic specialist stops at the top of the first corner, you can then save it so you dont have to go through all the last video clips again. Before you talk to her make sure you enter the gameplay options, and have the difficulty on Normal and "Squad Power Usage" set to no. This ensures your team only use abilities you command them too, which means the attacks count for your achievement and there's no chance of them doing it on their own.

As you're walking down the next corridor, after talking with her, 2 collector drones will fly by and a 3rd will fly by becoming Harbinger. Fire warps at it and then continue down. When you can see him again fire till his armor is at a level that your Incinirate Blast ability is a definate kill (varies upon your skill in it) and finish the Harbinger off with that. Take cover and wait for the next direct control posession and Warp again for the barrier, shoot a bit for the armor, then Incinerate Blast for the kill. It's important to note, the tracker will only appear every 5th kill that counts, so if it doesn't appear, that's probably why. Talk to your biotic and have her walk to the next area (kill the 3 husks on the way) and repeat the same stuff again till the enemies are all dead, talk with her a 3rd time (saves your progression) and then reload your save at the first corridor. Repeat until you have it.

But just to repeat (as it confused me) the tracker only appears at 5/10/15/20/25 kills, and wont show up on any others. Good luck with it!

Use incinerate on your enemies armour (their health bar will be yellow if their current defence is armour)

You can do this either with your character or by ordering a squad mate to use there power on the enemy. It will not count if the squad mate uses it without you ordering them.

I my case I used Moridin. I did this juring his loyalt quest and I played the game on insane dif. On insane both bloddpack (vorcha) and the (krogens) have amor and since you need to take Moridin with you anyway on this quest is nice and simpel. I focused on the varans and the vorchas as they come out mostly one by one and did not realy had a chane angisnt me one on one. If i had time I also used it on some of the krogens but this is not a fair fight if it comes charing at you.

I hope this helps out