A file with .apa extension is a software development project file created by RSView application. It contains information required for creating Human Machine Interface (HMI) applications. APA files are stored in archive file format. Its archival file format helps in transferring these from one computer to another easily due to smaller file size. Standard decompression utilities can be used to extract the contents of APA files. APA files can be opened using Rockwell Automation RSView Studio or RSView ME software.
APA File Format - More Information
The RSView application manager saves the .apa files by default to C:\Documents and Settings\All Users\Documents\RSView Enterprise\ME\Archives location on Windows XP. However, you can save the file to any directory as per requirement.