During the detection process, Symantec Data Loss Prevention either discards or truncates files that exceed the maximum file size setting for the file reader (
FileReader.MaxFileSize). When certain files are truncated (container files such as .zip, .pdf, and Office files ending in x (.docx)), the files become corrupt. Because the files are corrupt, no incidents are created even if there was policy-violating content in the file.
If you observe this behavior, increase the FileReader.MaxFileSize setting to ensure that large binary files are not truncated.