I'm guessing you mean to say that RoboHelp (2015 Release) was used to create an output and you are trying to open the output using Firefox and having issues?
Assuming that's correct, what is the output type please?
Responsive HTML 5
Multiscreen HTML 5
You assume correctly; and the output type is WebHelp.
thanks for responding,
And also the point version of FF – they might have changed something that the community isn’t aware of (it’s happened before to us)
Hmmm, I just tested using firefox version 43 and it worked. I was prompted to update firefox and now it's version 44.0.2 and RoboHelp 2015 Release WebHelp seems to work just fine.
Have you updated RoboHelp? If not, perhaps you need to.
There was an issue with a Firefox update. This was fixed in path 2 for RH2015.