D. Duplicate files should be removed while cleaning a master vendor file.
When cleaning a master vendor file, removing duplicate files is an essential step to ensure accuracy and avoid confusion. Duplicate files can create errors and make it difficult to manage and maintain vendor information. By removing duplicate files, you can streamline the process of managing vendor information and avoid the potential for incorrect payments or other issues.
While it is also important to discard old vendor files that are no longer needed, recopy messy files, and remove incomplete files, these actions are not as critical as removing duplicate files. By focusing on removing duplicates first, you can ensure that you are starting with a clean and accurate master vendor file, which will make it easier to manage and maintain going forward.