I have seen this.
InDesign depends on the operating system to maintain this file association, and sometimes it can get bollixed.
You need to rebuild the Launch Services database.
It's easiest to install and use Onyx to do this: http://www.titanium.free.fr/download.php
May I thank you very much!
Rebuild the LSD with my beloved Cocktail and all returned to normal. So easy.
Had no clue, all the wiser now.
Once again: Thank you and cheers!
Although the method worked it has returned. In fact it returns twice or even three times a day.
Rebuilding the LSD so many times each day is not what I expect of 'top notch' equipment.
Do you, or anyone else, have an idea of how to solve this?
Indeed, you clearly need to find the source of the problem.
In my limited experience, this kind of thing happens when some program misbehaves and causes the LS Database to get corrupt. This usually happens as a one-time event, so rebuilding is an easy solution.
In your case, obviously the problem is chronic, so you will need to get to the bottom of it.
There is no reason to assume that InDesign is at fault. I'm afraid I don't have any tips for you. Contact an Apple support path, I guess.