InDesign CS6 is not supported by Adobe running under El Capitan or Sierra.
I have been running on both of these operating systems since they were released with no problems. it has only been since last Thursday.
Owners of old programs simply have problems with Mac El Capitan/Sierra... none of which is Adobe's fault... Adobe did not change your old program to make it stop working... Apple changed their operating system and THAT is why your old programs won't work, not because of anything Adobe did... Also... every time Apple issues an update, there is the risk that an old program that HAS been working will STOP working... bottom line, old programs require a matching old operating system
Thanks for your opinion on Apple, however the last update from Apple was on July 30th, so i am unsure why it would take this long to affect Indesign, all other Adobe applications are running just fine.
If anyone out there has any helpful advice it would be greatly appreciated.
If using InDesign is mission critical for your work I suggest you either revert your OS or upgrade to InDesign CC2015/2017.
Unfortunately, everything Derek and John already said is spot on. However, you might find this thread offers a ray or two of hope:
If you don't get anywhere with the recommendations, reconsider the previously-offered advice: upgrade to CC 2017 (supported on Sierra) or roll back your OS to one that supports CS6.
Since you've already deleted your preferences I would like to suggest one other thing which may or may not do anything for this particular problem but is always worth a try—deleting InDesign's cache files.
To do so:
With InDesign closed launch a Finder Window in column view and click on your home folder. With the Option Key pressed choose Library from the Finder Go Menu. Within the Library folder find the “Caches” folder. Within the Caches folder find and delete the entire file “Adobe InDesign”. I find that deleting the cache file completely leads to a lasting change.
This procedure is usually done when there is a problem within a panel or window but at this point it couldn't hurt.
Also in addition to the Adobe InDesign folder that you said you deleted in your Home Library Preference folder there is another file called com.adobe.InDesign.plist which at times has helped me by deleting it as well.
Yes that may work, and then one day you'll be finalising a job, doing the final corrections and bang the thing crashes and won't start. Sods law and computers ... you have to calculate if it's worth the risk.