What kind of links will break? Is there any specific character in the URL where it breaks?
So this is embarrassing. I've misdiagnosed the issue. Here's the situation. I created a book in InDesign CS6 and submitted it to BookBaby to be made into an ebook and distributed to Amazon, etc. BookBaby contacted me and said that most of my links (which are URL links) were broken. Not knowing why this had happened I asked what version of InDesign they were using and they said CC 2015. So I thought that meant in the conversion of my file from CS6 to CC 2015 that the links were broken. At the time I did not have access to my CS6 file but now I'm home and I see that my CS6 file also has many broken links. So its not something that happened in the conversion to CC 2015, its something that was there in the file I submitted to BookBaby. But there still is a problem: how did most of my links become broken? Good news is that I have a slightly older version of the file from Monday and ALL the links in that file are good. Somehow between Monday and Wednesday (when I submitted the file to BookBaby) about 300 of my 350 links became broken. There doesn't seem to be any rhyme or reason to which ones still work and which ones do not. The good news is I guess I can take my Monday file and make the final edits to it (again) and I'm back in business. But I just am very frustrated not knowing how so many links mysteriously became broken. And when I say broken, I mean in the hyperlinks window there is a red dot with a question mark and when I have a link selected and then choose Hyperlink Options from the little dropdown window in the upper right corner of the window the Destination URL window inside the popup window says: "http:// " whereas it should have the complete address. Any thoughts on the matter are greatly appreciated.