If you are sure that the .dat file is PDF and want to open it as a PDF, right-click on the .dat file and select Open with. Then, you will see the list of programs to open with.

Once you find the information, repeat Steps 1 and 2 to open the .DAT data file in that program. Advertisement. Article continues below this ad. More For You. How to Transfer a File Using USB.

It's a straightforward website that lets you upload and open DAT files without needing to sign up or provide an email. Simply drag and drop your file into the box. Keep in mind there's a 50MB file ...

If the DAT file is a video, you can open it with its associated video app. However, if you aren't sure what app it's intended for, VLC Media Player should be able to open it as well.