Thought I would post this as I just spent $100 trying to recover files and have discovered the solution. Probably pretty straight forward, but maybe it will help someone.
I am working on a project and sync'd and editing multiple scenes for an 8 day shoot. The same production had a month or so hiatis, went back into filmming and have another 30+ days. In the mean time I upgraded systems, but had everything for the project stored on an external drive. Or so I thought. I started working with the new footage, but when I went back to tackle an old scene I had realized that all my audio was offline (I AMA linked my video but imported my audio). I freaked out.
I then realized that I had some old setting when first importing audio from two months prior that went to a different hard drive which had already been cleaned. I bought some software, recoved the files and tried to rebuild the data base. Unfortunately, it didn't work. I tried relinking, still didn't work. I figured since Avid just needed the timecode and source file name, maybe I could just reimport the audio and relink. Worked like a charm. Now all my audio is syncd up just how I had it before and on my main drive.
Again, this all probably seems fairly obvious but I spent hours going the long way around before getting here and couldn't seem to find anything online about it. Hope this helps someone in the future.