Hi. I've been having this issue for probably the better part of half a year. My IT guys have been through it and crash reports without being able to help. I've done everything I can but nothing is working. Here's the whole story, tho it's vague.
I'm using CS6 INDD 8.1 on a brand new 27 inch iMac running El Capitan 10.11.6. But this problem existed on my old iMac too when it was running Yosemite. I did a fresh install of all my apps on the new Mac. I have deleted preferences many times. The crashing happens when I'm working from my server or locally. It started out that the crash would happen when I was trying to place an image. Now, it happens when I open files, click on a box. It's almost entirely random and it's even just crashed when it's sitting idle. I have posted here before showing crash reports, but no one could help me. And now, InDesign isn't even showing the crash reports.
I'm at my wits end and I'm out of options. I'd burn chicken feathers and slaughter a lamb if I thought it would solve my issues for once and for all
I don’t know what the issue was on the old Mac but I can tell you with 100% certainty that CS6 is not supported under El Capitan. Beyond trashing your preferences there is nothing I can think of.
I would advise you to at least download the CC2015 demo to see if it works. If so, a subscription may be your only choice if you want to continue with InDesign.
For the foreseeable future, upgrading to CC is not an option
Not sure what to tell, then. Sorry.