Originally Posted by CougarMurphy

i have the same exact problem and its been happening to me since i got the phone, each time i've been trying multiple things to try to fix it. What i noticed helpe for me atleast is change the limit to a WAY lower number.. I used to have it at 1000 or something crazy, and it would always delete everything around 300-400 texts in a single thread. So i lowered it to 250 and i've been good for months, so it may have something to do with the limit. i been trying to increase it by 10's to see how far i can take it before it dumps all my texts. i'm at 280 right now. So we'll see, other than that just try lowering the limit and you should be good, havent delete my inbox in a long time, so i know this has atleast helped me, give it a try..