What is File Validation Utility (FVU)? The FVU facility, also known as File Validation Utility, allows you to validate e-TDS/TCS return files. As part of its services, NSDL provides this utility. Deductor return files are verified by the FVU in accordance with the prescribed formats. The utility facilitates the submission of error-free e-TDS/TCS returns. Gen TDS software and the Tax Information Department's website offer this service. The Gen TDS Software can help you generate the FVU file by downloading and generating it. We also discussed the basics of FVU files and how they are created.