However, there is another method. In this case, you can use your Notepad to create a batch file, which will rename all the file extensions in a specific folder and all sub-folders at once.

How to convert .dat files to .csv? Right-click on the DAT file > Open with > Notepad. Next, save the Notepad TXT file as a CSV file, using the Save as option and giving it a .csv extension. Now ...