I am having a problem with IE 10 attempting to open a link in a webpage, where it links to a file with extension .tr5. I have found out that his happens even when I create a simple html file and have the link to the file in there, so for example I use this html file:
<!DOCTYPE html>
<html>
<body>
<a href="http://xxx.xxx.xxx/__data/assets/file/0006/1104/Corporate-Organisation-and-Management-Communications-Organisational-Charts-Headquarters-HQ.tr5">
This is a link</a>
</body>
</html>
What happens is that this link is always opening inside IE and I see the contents of this .tr5 file as text, where as I used to see the download prompt on IE 8, and I still see the download prompt on IE 10 through compatibility mode. Interestingly firefox also has the problem where it is opening the content of .tr5 file in the browser itself as text.
The .tr5 file extension itself is set to open with TrimDesktop.exe which is expected, and .tr5 files do open with the correct program. Also, if I were to right click the link to a tr5 file inside IE 10 and choose "save target as", I am allowed to download the file.
As an experiment, I altered the a href link above to point to a new file I made with .xxx extension, and this time I was prompted to download. So it appears that IE10 and firefox are deliberately trying to open these tr5 files within themselves.