What Should I Do About this Warning: "Warning: A Work File Failed. Calculations will be Retried. No data has been lost."?
This is just a warning message not an error message so there is nothing to fix. This is a internal timing issue when the MOVES worker tries to access a file and there is a lock on it. This lock could be from Windows Index service, or your antivirus software momentarily accessing the file. You could remove indexing from the folder in question and also tell your antivirus software not to scan that folder.
MOVES calculations will be redone and no data will be lost and the results will not be affected.