Atom files are called Atom Syndication Format files. The Atom format offers the possibility of platform-independent information exchange. Likewise, RSS can be easily published with Atom changes, for example, new articles and headlines on websites (eg blogs, news sites, etc.).
These XML-based text files can be edited in any text editor, but they should be created or edited using an RSS / Atom authoring program. If an ATOM file is made available for download from a web page, you need a reading program, a so-called feed reader (aggregator), which then regularly collects the data from the respective page.
Even browsers can be used (sometimes with a plugin) as a feed generator or feed reader.
Most often resolving problems with opening ATOM files is very simple. Just install an appropriate program that supports such files. All of the listed programs support ATOM files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of ATOM files or offer file conversion options, but may not be capable of editing such files.
It is possible that although a compatible program has been installed on user’s system, it is not used by the system to open it. This may happen because no default application was associated with this type of files. To associate ATOM files with given application, select "Open with" from drop-down menu (accessed by right-clicking on the file). Then select from the list the program or application you want to be used to open this type of file. If the Safari applications is not on the list, select "Browse" option in order to manually locate the directory where Safari has been installed.
Sometimes problems with opening ATOM files may not lie with the application itself, but can arise due to other causes, such as: