I'm currently in the process of obtaining retroactive forbearance through Fed Loans and Navient. Anyone, feel free to correct me if I'm wrong about any of this. Also going to piggy back ALLgoodABQ here.
A retroactive forbearance will show your account was is forbearance from one of past date to another. For example, in my situation, I unfortunately went through a bad divorce, went through an episode of depression where I stopped caring about lots of things, including making payments on my student loans. I'm now recovering and trying to make right with my loans.
I have up to 12 months of late payments. What the retroactive forbearance would do is show my account was in forbearance from one past date to another (i.e. showing I was in forbearance the past year). Instead of having late payments, it shows you were in good standing because you were in forbearance.
Some student loan providers will grant retroactive forbearance for maybe only 90 days back, 6 months back etc. It depends on the provider. With FedLoan, I qualify for an internship/residency retroactive forbearance since I've been in an internship the past few years. I'm in the process of sending the paperwork to them showing I've been in this state internship, and from what the representative informed me on the phone, they would be able to go back to 12 months with the retroactive forbearance. If you're not in an internship, or in the military, you'd just have to call and explain your circumstances and ask how far they can go back with the retroactive forbearance.
But please remember, retroactive forbearance does not automatically make your credit go up (I'll get to how you can make it go up). The loan provider will not report this to the credit bureaus due to the fact they know you were not making payments and you were not in good standing. This is why it's critical to obtain a letter from them showing the forbearance was applied from date X to date Y. Because you can send such a letter to the credit bureaus, and from reading multiple threads on here, the letter (combined with a form contesting your credit reports), can ultimately lead to the bureaus updating your credit reports showing you were in good standing, therefore making your score go up. There's actually a legal loop hole people have been using where he bureaus should be updating the report based on this information. If you need the statutes I can pull them up.
As for Navient, they supposedly approved a 12 month retroactive forbearance for me. They sent a vague letter stating I was approved for a forbearance, but not for what days retroactively. When I asked if I could get a letter with the past dates I was approved for I was met with "We can't do that. But we can do a verbal confirmation." After a bit of nagging and pushing and reinforcing this was just for my documentation, she agreed they can send a letter with the dates, but also the date I requested the forbearance (which I may not include to the credit bureaus because it would defeat the purpose in disputing).
Sorry this was long, but hoped it helped! Remember, call and ask for the retroactive forbearance and see how far they can go, obtain a letter showing you were in forbearance those past dates, and then dispute the credit bureaus with a dispute request and the letter. Hopefully that will make your score go up. I'm crossing my fingers it will for mine.