I just hope this does NOT happen again. For those asking for a solution, a simple answer is there is none. If the files are corrupted you will just have to re-download… You can keep a copy of the correct base game on some external drive as a prevention… If the game gets corrupted again you might delete the game and copy the original files, that could save you 170 GB of data… I did laugh a lot (sad laugh), quite the amateur hour by Activision 
.