The AEPX file extension is used by the Adobe After Effects video compositing and animation software for XML-based project files. In addition to references to videos, audio files and images, AEPX files also contain cut and timeline information and effects settings.
Usually, the paths to the media files are also saved, so that they are only found if they are in the original directory. But you can also load AEPX files and specify new locations for missing files.
AEPX files contain almost exclusively readable information, so that, for example, changed paths or media names can be easily adapted via text editor. Aepx project files are designed primarily for automated (via script) modification of project settings.
Adobe expressly points out that AEPX should not be used primarily for projects. Therefore, AEPX files can only be saved under 'File -> Save as XML'. In addition, AEPX files can be quite large and are then processed slower.
The AEPX format is supported since version CS4.
Most often resolving problems with opening AEPX files is very simple. Just install an appropriate program that supports such files. All of the listed programs support AEPX files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of AEPX 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 AEPX 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 After Effects applications is not on the list, select "Browse" option in order to manually locate the directory where Adobe After Effects has been installed.
Sometimes problems with opening AEPX files may not lie with the application itself, but can arise due to other causes, such as: