Just to be clear, the Bitlocker "failure" didn't cause the loss of data.  The OP just couldn't access it; whether that was an actual failure or just a lost key (the info necessary to unlock bitlocker) is unclear.  The instructions are VERY specific that if you lose that key - you are out of luck.  So, don't lose it.  

Having current back-ups solves the problem of the missing data.

I use bitlocker on multiple devices & have had NO problems (I use Lacerte).