Word does not open link because it does not recognise the extension

[Isa.G]

I am asking you about the problem I have with Word because it does not open links when they have an extension it does not know.

I sometimes receive pdf files that my favourite reader does not open and in those cases I open them with another reader and to differentiate those files I change the extension to pdf1 so that the other program opens them.

In Windows it works fine. The problem is when I place a link inside a Word file to pdf1 because I get a warning that it cannot be opened because there is no associated program, when this is not the case.

How can I solve it?

Thanks