Oasis montaj is by default installed as "Desktop Applications 9" in the "Program Files\Geosoft\" folder of your "C:" drive. Certain files required to support 32-bit interoperability may be installed in the "Desktop Applications 9" folder of "Program Files (x86)\Geosoft\", but these can be disregarded for developers who intend to extend Oasis montaj or create stand-alone 64-bit programs.
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Additionally, there is a folder specific to any Windows user. This folder is located at %USERPROFILE%\Documents\Geosoft\Desktop Applications 9. It It is reserved for user files and user customizations and has the same structure as the main folders. For example: Geosoft menu files are stored in C:\Program Files\Geosoft\Desktop Applications 9\omn, and and any customized menu files you create must be stored in %USERPROFILE%\Documents\Geosoft\Desktop Applications 9\omn.