What Is an ADP File?

A file with the ADP file extension is a Microsoft Access Project file. They hold Access project information and communicate directly with a Microsoft SQL Server database, but don't contain tables or queries like ACCDB files.

The ADP format is no longer supported starting in MS Access 2013, but you can read more about the ADP format and how to work with them in supported versions of Access at Microsoft's Office Help and Training.

Though much less common, ADP files may instead be audio files used in some video games. Still, others may be videos downloaded from video streaming websites.

Note: ADP is also a payroll service company. If you're dealing with files pertaining to that, see ADP.com.

ADP files that are used with Microsoft Access can, of course, be opened with the program, too, but only if you're running a version older than Access 2013; they also don't work with SQL Server 2012 or newer.

I'm not aware of a media player or other tool that can open ADP files that are ripped (copied) from video game discs, nor do I have a download link for an ADP video player. Video files in the ADP format are usually downloaded from browser add-ons like Video DownloadHelper in Firefox.

Note: Something you can try if you have an ADP video file is to rename the video to have the .MP4 file extension (e.g. videofile.adp to videofile.mp4). This is only going to work if the file is actually an MP4 but was incorrectly named with .ADP during the download process.

If you find that an application on your PC does try to open the ADP file but it's the wrong application or if you would rather have another installed program open ADP files, see our How to Change the Default Program for a Specific File Extension guide for making that change in Windows.

See this thread at the Microsoft Office Dev Center, or this one at Access Experts, for some info on converting an ADP file to ACCDB. This isn't a classic "file in, file out" type of conversion like you see with dedicated file converters, but it might be what you're in need of.

Just as I don't have any information on opening ADP audio or video files, I also don't know of any tools to convert them to MP3s, MP4s, or any other audio/video format.

See Get More Help for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what kinds of problems you're having with opening or using the ADP file and I'll see what I can do to help.