Version 3.0 of Harvard Graphics used the suffix CH3 for files containing charts and their related data. The extension was also used for files that contain special chart types.
Harvard Graphics was taken over by Serif, but no longer uses the ending.
Most often resolving problems with opening CH3 files is very simple. Just install an appropriate program that supports such files. All of the listed programs support CH3 files, but may vary in offered function and purpose. Some programs may be capable only of viewing contents of CH3 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 CH3 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 Harvard Graphics 98 applications is not on the list, select "Browse" option in order to manually locate the directory where Harvard Graphics 98 has been installed.
Sometimes problems with opening CH3 files may not lie with the application itself, but can arise due to other causes, such as: