This has been an ongoing (since the beginning of time) issue for me. I usually develop using the latest version while my users are on a previous version. I have both versions installed on my machine for testing purposes, currently Advanced 16 and Advanced 15.
Every time a new FileMaker product is installed or updated, that product takes over as the default application. With the release of 15.0.4, Advanced 15 is now the default on my machine. Manually setting the default in Windows never works. The only solution I have come up with is to update or reinstall the version I want to be the default.
Anyone found an easier way to reset the default?