Where are my posts?

I am using nightly builds, I updated to build 10-14 and 10-16 then discovered that I can’t find some of my posts. I checked the time stamps of all contents and discovered that only posts within May-October 2004 and below October 1985 remained accessible. I tried locating the lost articles in my database but they are nowhere to be found. I tried updating to build 10-18 but nothing happened. I think I’ve lost them.
What possible things went wrong?