It seems to think that the source file is not within the Project.
Method
1. Looking at attached source in individual's property box
2. Click to Add Media
3. Insert from file

4. Navigate to file (already downloaded to the correct folder)
File is situated within folders within Media for the Project

5. Select file and click Open
6. Warning come up telling me that
'The media will be added to the current project...'
It tells me which folder the file will be copied to
However, this is the same folder that the file is in and will duplicate it.

This is not confined to a single project, it occurs on at least 3, some of which haven't been touched for a while.
I've uninstalled and re-installed FH
Something tells me that this is something quite simple and fundamental
Any help would be much appreciated..
System
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FH v6.2.7
Windows 7
Parallels 15.1.1 on iMac