Files copied to Main hard drive regardless of the settings

I am running FCP X Version 10.2.3 on OS 10.11.6. and using a Mac Pro, Late 2013. When I import media, the files are copied to the FCP Library folder on my main hard drive. I want them left on the external drive. I have trashed my preferences, I have the setting turned on in preferences under "import settings" to leave the files in place, and also have the leave the files in place setting turned on in the "media import" dialogue window. That is the only setting checked in the media import dialogue box. The media files are being copied to the FCP Library folder on my main hard drive anyway, resulting in a full hard drive. If I continue the edit without letting the files copy to the FCP Library folder I can edit the video, but it will not share. If I close FCP and reopen I lose the links on a lot of the clips. Any idea why FCP will not let me leave the clips on an external drive?