This will happen every time you will attempt to verify the game. Generally it is totally OK to have 1 or 2 files fail to validate. For the rest of the text: "and will be reacquired" has always made me think that the game will recover these files once you successfully relaunch the game. If it makes you feel better about this situation, my personal download works entirely fine, but if I verify the files, this 1 file will also fail to validate on my side of things.
Involving your file corruption, I would suspect it would be due to the save process being interrupted. The way you phrased this makes me believe that it is a consistent issue. If it is truly consistent, I would suggest ensuring that Terraria actually has access to these files by doing your classic troubleshooting methods:
1) Running the program as administrator.
2) Running the program in compatibility mode (I have found that windows 8 works just fine for compatibility mode settings).
3) Allowing Terraria as an exception to your firewalls and/or anti-viruses
4) Possibly disabling these programs.
Of course it could not be blocked directly, if this is the case, may want to consider not using cloud save, and always leaving the game through the save and exit option.