D21 File Type- The quick facts
What are D21 files and how to open them
Are you having problems opening a D21 file or just wondering what they contain? We explain what these files are used for and show you software that we know can open or otherwise handle your files.
What is a D21 file?
The D21 file extension indicates to your device which app can open the file. However, different programs may use the D21 file type for different types of data.
While we do not yet describe the D21 file format and its common uses, we do know which programs are known to open these files, as we receive dozens of suggestions from users like yourself every day about specific file types and which programs they use to open them.
We are continually working on adding more file type descriptions to the site, so if you have information about D21 files that you think will help others, please use the Update Info link below to submit it to us - we'd love to hear from you!
How to open D21 files
Important: Different programs may use files with the D21 file extension for different purposes, so unless you are sure which format your D21 file is, you may need to try a few different programs.
While we have not verified the app ourselves yet, our users have suggested a single D21 opener which you will find listed below.
Various apps that use files with this extension
These apps are known to open certain types of D21 files. Remember, different programs may use D21 files for different purposes, so you may need to try out a few of them to be able to open your specific file.