Here is a breakdown on how to save everyone through the ending of Mass Effect 2 and get the No One Left Behind achievement or trophy. Apart from the ubiquitous revelation that you're walking into a suicide mission, there are no other spoilers here.

Most importantly:

• Loyalty: Get max loyalty with everyone to guarantee their survival. You'll be using a majority of your team in someway or another. It's imperative that you do this because normal/non-loyal team members are bad choices for any kind of mission (especially escort or your own team). Some people have reported success with non-loyal members on lower difficulties but it's very much a hit-and-miss kind of thing. Get your conversation hat on and get them loyal.
• Ship Upgrades: Get the following ship upgrades: Armor (Jacob), Shields (Tali) & Thanix Cannon (Garrus)
• Pick the right team: You have to choose the right people for every job. The selection is usually very limited and the following table can help you figure out who goes where.

The following factors also come into play:

• Weapon & Research Upgrades: Not a priority but it helps to research character specific upgrades like Jack's L5 Implants since it makes them more viable for their respective roles.
• Alignment: Your Paragon/Renegade alignment don't make a direct impact on who gets to live but they are essential in gaining your teammates' trust. Some dialogue options are only available at 75% or higher. If you lose the trust of a team member, you need 100% alignment to win them back.
• Specialists: Assign specialists for each job, hybrids don't cut it. The requirements for each sub-mission will be made fairly obvious to you by the game itself. Pay close attention to the dialogue options and choose carefully as to who does what. Refer to the following table if you need directions.
• Mission Dependencies: Often the success of one squad member will effect the life of another - all the sub-missions are connected somehow. Look at all your choices if you think a team member is dying in spite of being the right person for the job.

If you satisfy the above conditions, Shepard will survive. In addition, if you want everyone else in your team to make it through (for the achievement), these following approaches are known to work:

FAQs/More Strategies

• Dealing with non-loyal team members - Miranda/Jack situation - If Miranda or Jack (or any other character) are not loyal, they have a tendency to die during the final cutscene, even if you don't use them. Here is a possible solution that works on Normal difficulty - pick a weak final team and send a weak loyal character on escort. Recommended characters to take with you are: Tali, Samara, Thane, Kasumi, Miranda or Jack (who ever is loyal). Send someone like Mordin on escort as well. The aim is to leave behind a physically strong ground squad (characters like Garrus, Legion, Grunt, Zaeed). The reason is the game tallies up some kind of hidden score and your ground team's chances of survival increase if you leave behind more number of tough fighters. Just as an example, on my Insanity playthrough, I used Garrus+Grunt for the final battle and Mordin ended up dead. To fix this, I used Miranda+Grunt instead and everyone survived.
• Dealing with non-loyal team members (the lazy way) - You can always turn down the difficulty to Casual and not use the disloyal member at all.
• Random death of loyal team members - There are certain combinations where a loyal team member dies during the final cutscene for no apparent reason. I found that changing your final team can help solve this. Like the above case, a good general strategy would be to take a weaker team with you to the final battle; just make sure they are all loyal. For the rear guard, leave behind strong, combat focused characters that can hold their own in a firefight. Characters that work well for this are Grunt, Thane, Zaeed and Legion. Characters that have a tendency to die in this scenario are Mordin, Tali, Kasumi and Miranda.

• Trouble in vents ? - If your tech specialist is taking one in the head in spite of all the upgrades & max loyalty, try changing your 1st squad leader to Garrus/Miranda.
• Picking an escort - As long as the rest of the squads do their job perfectly, the escort choice is almost inconsequential. Just make sure he/she is loyal and they will all survive. It's a good place to send your wimpy characters to.
• Escort dying ? - In the odd case that the escort dies, try switching your 2nd (Fire) Squad Leader to a loyal Garrus or Miranda.

• Mordin - Quite a few people are having trouble with Mordin dying for no apparent reason, even with max loyalty and all. Try using him as an escort or even part of your final team to fix this problem.
• Saving the Normandy Crew (NPCs) - This depends entirely on how quickly you decide to use the Omega 4 relay. If you want to save everyone, use it as soon as it is available. The relay opens exactly one mission after the IFF and its recommended you use that time for Legion's loyalty mission. Any time wasted on side missions or other loyalty quests at this point will result in loss of lives. Your final team makeup will have no effect on who survives. The NPCs don't matter for the achievement.

Flow chart

The guys at Game Informer produced this flow chart back in June which presents the above information in a nifty format. You can view the hi-res version here (just hit the zoom in button at the center) or download it from the original GI article here.

If all else fails...

Turn down the difficulty setting from the Options > Gameplay menu. Team members with Normal loyalty have a higher chance of dying on the harder difficulty settings. If you just want the achievement or maybe want a perfect save game for ME3, just swallow your pride and turn it down to Casual. It might save everyone's hide.

Thanks to the GB community for all the feedback. If you finished the game, please do tell what worked (or DIDN'T work) for you and I'll add your strategy to the list.

Here is a breakdown on how to save everyone through the ending of Mass Effect 2 and get the No One Left Behind achievement or trophy. Apart from the ubiquitous revelation that you're walking into a suicide mission, there are no other spoilers here.

Most importantly:

• Loyalty: Get max loyalty with everyone to guarantee their survival. You'll be using a majority of your team in someway or another. It's imperative that you do this because normal/non-loyal team members are bad choices for any kind of mission (especially escort or your own team). Some people have reported success with non-loyal members on lower difficulties but it's very much a hit-and-miss kind of thing. Get your conversation hat on and get them loyal.
• Ship Upgrades: Get the following ship upgrades: Armor (Jacob), Shields (Tali) & Thanix Cannon (Garrus)
• Pick the right team: You have to choose the right people for every job. The selection is usually very limited and the following table can help you figure out who goes where.

The following factors also come into play:

• Weapon & Research Upgrades: Not a priority but it helps to research character specific upgrades like Jack's L5 Implants since it makes them more viable for their respective roles.
• Alignment: Your Paragon/Renegade alignment don't make a direct impact on who gets to live but they are essential in gaining your teammates' trust. Some dialogue options are only available at 75% or higher. If you lose the trust of a team member, you need 100% alignment to win them back.
• Specialists: Assign specialists for each job, hybrids don't cut it. The requirements for each sub-mission will be made fairly obvious to you by the game itself. Pay close attention to the dialogue options and choose carefully as to who does what. Refer to the following table if you need directions.
• Mission Dependencies: Often the success of one squad member will effect the life of another - all the sub-missions are connected somehow. Look at all your choices if you think a team member is dying in spite of being the right person for the job.

If you satisfy the above conditions, Shepard will survive. In addition, if you want everyone else in your team to make it through (for the achievement), these following approaches are known to work:

FAQs/More Strategies

• Dealing with non-loyal team members - Miranda/Jack situation - If Miranda or Jack (or any other character) are not loyal, they have a tendency to die during the final cutscene, even if you don't use them. Here is a possible solution that works on Normal difficulty - pick a weak final team and send a weak loyal character on escort. Recommended characters to take with you are: Tali, Samara, Thane, Kasumi, Miranda or Jack (who ever is loyal). Send someone like Mordin on escort as well. The aim is to leave behind a physically strong ground squad (characters like Garrus, Legion, Grunt, Zaeed). The reason is the game tallies up some kind of hidden score and your ground team's chances of survival increase if you leave behind more number of tough fighters. Just as an example, on my Insanity playthrough, I used Garrus+Grunt for the final battle and Mordin ended up dead. To fix this, I used Miranda+Grunt instead and everyone survived.
• Dealing with non-loyal team members (the lazy way) - You can always turn down the difficulty to Casual and not use the disloyal member at all.
• Random death of loyal team members - There are certain combinations where a loyal team member dies during the final cutscene for no apparent reason. I found that changing your final team can help solve this. Like the above case, a good general strategy would be to take a weaker team with you to the final battle; just make sure they are all loyal. For the rear guard, leave behind strong, combat focused characters that can hold their own in a firefight. Characters that work well for this are Grunt, Thane, Zaeed and Legion. Characters that have a tendency to die in this scenario are Mordin, Tali, Kasumi and Miranda.

• Trouble in vents ? - If your tech specialist is taking one in the head in spite of all the upgrades & max loyalty, try changing your 1st squad leader to Garrus/Miranda.
• Picking an escort - As long as the rest of the squads do their job perfectly, the escort choice is almost inconsequential. Just make sure he/she is loyal and they will all survive. It's a good place to send your wimpy characters to.
• Escort dying ? - In the odd case that the escort dies, try switching your 2nd (Fire) Squad Leader to a loyal Garrus or Miranda.

• Mordin - Quite a few people are having trouble with Mordin dying for no apparent reason, even with max loyalty and all. Try using him as an escort or even part of your final team to fix this problem.
• Saving the Normandy Crew (NPCs) - This depends entirely on how quickly you decide to use the Omega 4 relay. If you want to save everyone, use it as soon as it is available. The relay opens exactly one mission after the IFF and its recommended you use that time for Legion's loyalty mission. Any time wasted on side missions or other loyalty quests at this point will result in loss of lives. Your final team makeup will have no effect on who survives. The NPCs don't matter for the achievement.

Flow chart

The guys at Game Informer produced this flow chart back in June which presents the above information in a nifty format. You can view the hi-res version here (just hit the zoom in button at the center) or download it from the original GI article here.

If all else fails...

Turn down the difficulty setting from the Options > Gameplay menu. Team members with Normal loyalty have a higher chance of dying on the harder difficulty settings. If you just want the achievement or maybe want a perfect save game for ME3, just swallow your pride and turn it down to Casual. It might save everyone's hide.

Thanks to the GB community for all the feedback. If you finished the game, please do tell what worked (or DIDN'T work) for you and I'll add your strategy to the list.

I took a slightly different approach to competing the suicide mission and came out on top with everyone alive, including myself. Had Jack do the shield and Legion do both the vents and escort. Phenomenal experience. I'm pretty satisfied with ending I achieved in just over 30 hours.

I saw a video of some fucker who blasted through the game in 10 hours and

I am totally going to follow this list Thanks!

I am just wondering, how apparent will these options be? Will their just be a conversation and one will say we need someone for shields and you choose?

Thanks, good info (the "equip everyone and everything" part was obvious enough, but the team leader stuff is a surprise). But I'm just gonna go in blind and live with the consequences. Seems like it'd be more fun that way.

So you're saying that I'm going to have to talk to Samara and Subject Zero to get the best ending?  
 
Well, screw dat, yo. 
 
Although, if Samara and Jack did end up dieing, I'd probably call that a pretty fantastic ending, so I won't complain.

Ahh, so Legion will be a member of your party. Outstanding.

I did
Doors : Legion
Squad Leader #1 : Miranda
Squad Leader #2 : Miranda
Shields : Samara
Escort : Grunt
 
and nobody died... I didn't even know people would die if I would pick wrong choices lol, good thing I picked right.

 I used Grunt and Garrus; those two and Shepard survived. I had Jacob do the Vents; he got pwned. First squad leader was Thane, who died too. Used Samara for the biotic shield and Legion for escort- both of them lived. Second squad leader was Jack. I pissed her off (big surprise) and didn't have enought Paragon/Renegade to regain her loyalty. Out of spite I used her as cannon fodder but it didn't occurred to me that it would affect everyone else. I lost Jack and subsequently Mordin :( 

I believe it is based on loyalty because the people that were not loyal to me...died on me 
 
 
EDIT : forgot to mention...I chose Legion for the first job and then Garrus for the squad leader (both) and samara for the shield 

I didn't read the whole post, because I want to roll without any sort of guidelines first. That said, I'm flabbergasted that you can keep everyone alive.

Thank you so much. I'll make sure I follow everything.

Thanks!  I'll definitely refer to this when I get my copy of the game :)

Would like to correct you on the "All ship upgrades" thing. The medical bay upgrade is NOT required.

How do I get all the materials without going into the console and manually punching in the code for it.  >.>
 
I'm not scaning all these planets and whatnot, please tell me there is an easier way.

" How do I get all the materials without going into the console and manually punching in the code for it.  >.>  I'm not scaning all these planets and whatnot, please tell me there is an easier way. "

" @KaosAngel said:

" How do I get all the materials without going into the console and manually punching in the code for it.  >.>  I'm not scaning all these planets and whatnot, please tell me there is an easier way. "

You answered your own question, scanning planets. I didn't find it boring at all, just as long as I exclusively mine Rich planets. The loot that you find on-ground won't get you enough. "

I chose Jack's side in that fight between her and Miranda, how do I get Miranda's loyalty back?

" @RedSox8933: Well I picked Miranda because Jack needs to chill the hell out and stop trying to start mass effect fields in the middle of my ship. Anyways I lost jacks loyalty - Would like to know how to rectify either : / Sucks not having the sexy circle under there Squad Select pic ; D "

Thanks. Just finished the game. Jack keeps saying "Fuck off" every time I talk to her though. That happened to anyone?

I sent Tali to escort the survivors, everyone survived. 
Legion in the vent, Miranda leader of both teams, Tali for the escort and Samara shielding,

" @gosukiller: No those were greyed out. And now when I try to talk to Miranda there is a renegade and a paragon option but they are also both greyed out. "

" @RedSox8933 said:

" @gosukiller: No those were greyed out. And now when I try to talk to Miranda there is a renegade and a paragon option but they are also both greyed out. "

Get them (Paragon, Renegade) higher. Haven't played yet though, is the Karma system still similar (ie, two meters and two different "skill trees" for Charm/Indim?). "

First time I just followed my gut and lost 4 guys =\
I did it the second time around for the achievement and everyone lived :D

For me, Jack, Mordin, Grunt, Jacob, all died.
Next playthrough, I'll just try to make better decisions, but I will have to deal with who lives and who dies. And this is the file that I will carry over.

You don't need to buy all the ship upgrades to have your squad survive. You only need three which are the hull and shield upgrade and then the Thanix Cannon.

When Jack/Miranda or Tali/Legion fight, you must have 80% of all Paragon or Renegade points to keep their trust.  If you lose the trust of a member, you must have 100% of the total points to earn it back.

" For me, Jack, Mordin, Grunt, Jacob, all died. Next playthrough, I'll just try to make better decisions, but I will have to deal with who lives and who dies. And this is the file that I will carry over. "

" so i did everything right and everyone lived up to the point were i had to fight the boss. After words when i had to leave to the normady only fucking Mordin died for no reason. WTF i have no idea what i did wrong "

yeah everyone was loyal i have no idea why that fucker Mordin died

All I want is for Miranda to survive.  She's all that matters to me.

" yeah everyone was loyal i have no idea why that fucker Mordin died "

" All I want is for Miranda to survive.  She's all that matters to me. "