I'm almost finished the game and I'm at the point where I have to choose between Miranda and Jack. I told Jack to calm down and lost her loyalty. I know I can use Paragon to sort out the situation, but I still don't seem to have enough. I have about half Renegade points in the first section, only gotten by unavoidable points, and almost completely full Paragon. Surely this is enough, no? 
 
Can anyone help me out?

Weird. It worked for me at 75% which is past the last line before the end. I was able to do that one thing in Samara's mission too because of it.

just go to your upgrade terminal and redistribute your points stat points (don't have to change any of them) but that will multiply your existing paragon score and should fill it up.

Just wanted to say, I'm in the same boat. I hate Jack, so siding with Miranda wasn't hard to do. However, I really want that achievement,; keeping all members alive hahaha. Will try the tips mentioned above.

" Just wanted to say, I'm in the same boat. I hate Jack, so siding with Miranda wasn't hard to do. However, I really want that achievement,; keeping all members alive hahaha. Will try the tips mentioned above. "

My first time through ME2, I lost Jack's loyalty.  It's weird that if has the paragon and renegade options grayed out when you go to reconcile with her, because after returning to her with a full Paragon bar, it still wouldn't give me the option.  It's still easy to keep her alive, but I found that kind of strange.  My second time around I made sure to leave Jack's and Legions Loyalty missions to the end, that way I had enough paragon to deal with the situations.
 
Long story short, from my experience, I don't know if you can win her loyalty back.

First off, it's important to know that there is no constant amount of paragon or renegade needed to defuse the character conflicts in ME2.  It scales to your level.  All other things being held equal, if you play with a very scattershot approach to moral decisions, you will never have enough paragon to solve problems because the required amount will rise as the game goes on.  It's basically an example of how the game screws up character immersion by limiting your chances for success should you not mindlessly follow a mostly paragon/renegade route.  However, many classes have boosts to paragon/renegade ratings as part of their 4 pt. class skill.  Infiltrator can automatically max both of them, I believe.   

" just go to your upgrade terminal and redistribute your points stat points (don't have to change any of them) but that will multiply your existing paragon score and should fill it up. "

The same thing happened with Miranda on my latest playthrough.  When it came time to calm the two biotics down, I told Miranda to back off.  I did not realize at the time, that in order to get Miranda's loyalty back, I had to keep advancing my Paragon female Shepherd, until I had enough Paragon points to reason with her, and that didn't happen until I was close to starting the Suicide mission, which was late in the game.  I felt quite satisfied when I regained Miranda's loyalty. 

This happened after I did her loyalty mission.  It was an interesting experience to be sure.

That's odd, in all my plays I've never lost their loyalty, but I could have sworn they always had their fight earlier in the game.
 
I've always been able to use the paragon or renegade option to talk them down and retain both loyalty.

That's odd, in all my plays I've never lost their loyalty, but I could have sworn they always had their fight earlier in the game.  I've always been able to use the paragon or renegade option to talk them down and retain both loyalty.