The file extension APIN identifies the import / export filter files of the DTP (Desktop Publishing) solution Adobe InDesign. With InDesign, for example, you can create print templates and layouts for print products such as flyers, catalogs or brochures.
Using the APIN files, InDesign can read and write various image, text, and vector formats. However, the current version of InDesign does not seem to use APIN files.
Most often resolving problems with opening APIN files is very simple. Just install an appropriate program that supports such files. All of the listed programs support APIN files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of APIN 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 APIN 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 Adobe InDesign applications is not on the list, select "Browse" option in order to manually locate the directory where Adobe InDesign has been installed.
Sometimes problems with opening APIN files may not lie with the application itself, but can arise due to other causes, such as: