How to open .ATT file extension?

If you cannot open a new file that has been saved in the .ATT format you need to download the appropriate software. The manufacturer of .ATT files is N/A; .ATT files belong to the Web Files category. After downloading the application from the list available on our website just run an unknown file, and as the default set the newly installed application supporting the .ATT files. Activities performed in the order described should solve the problems with all the files in the .ATT format.