Q: Somebody sent me an article in FDF-format. What are FDF-files and how do I open it.

A: Basically, FDF-files are really PDF-files saved under another name. Acrobat Reader should be able to read them natively, while eg Foxit PDF Reader requires you to rename the file extension FDF to PDF.

* From <http://www.planetpdf.com/mainpage.asp?WebPageID=338>:

"FDF is the file format used for Acrobat Forms and is used when submitting Form data to a server, receiving a response, and incorporating it back into a Form."

* From Elsevier <http://ees.elsevier.com/robohelp4.0/Author/FAQs/PDF_FAQ.htm#Q10>:

"The submission file I downloaded is in FDF format and not PDF format and I am having problems viewing it. What should I do?

An FDF (Forms Data Format) file is an alternate version of Adobe Acrobat’s PDF (or Portable Document Format). Either file type should be viewable within Adobe Acrobat. If you cannot get your system to view the file, try saving it to your local computer and changing the file extension from FDF to PDF. If you launch the file manually from your local machine, it should open properly.

If you are using a Mac, the default Preview software may not recognize the FDF file type. Please try changing the file extension to PDF or launching it within Acrobat Reader if possible.

If you are using a Windows-based PC with Acrobat Reader 6.0 or higher, to permanently configure your browser to handle FDF files:

Open up the My Computer icon from your desktop and select the Tools option from the menu bar at the top.

On the Tools menu please select the Folder Options item from the menu.

Now select the File Types tab from the window that appears. Scroll down through the various file extensions until you see the abbreviation FDF.

Make certain that this file type is set to be opened with either Adobe Acrobat or Acrobat Reader version 6.0 or 7.0. If it lists another program, click Change and select the correct version of Acrobat.

If this file extension does not exist please select the New option.

Type in the file extension FDF in the blank area of the new window that appears and click Ok.

Find the file extension, select Change, and pick the correct version of Adobe Acrobat or Acrobat Reader to open FDF files."

HTH.