I Cannot Associate Oxygen With a File Type on My Windows Computer

I cannot associate the Oxygen application with a file type on my Windows computer by right clicking on a file in Windows Explorer, selecting Open With > Choose Program and browsing to the file oxygen.exe. When I select the file oxygen.exe in the Windows file browser dialog the Oxygen application is not added to the list of applications in the Open With dialog. What can I do?

The problem is due to some garbage Windows registry entries remained from versions of Oxygen older than version 9.0. Please uninstall all your installed versions of Oxygen and run a registry cleaner application for cleaning these older entries. After that just reinstall your current version of Oxygen and try again to create the file association.